diff --git a/Packetery/Checkout/Block/System/Config/Form/ApiKeyValidate.php b/Packetery/Checkout/Block/System/Config/Form/ApiKeyValidate.php
index 6ed201ac..3daaa1e2 100755
--- a/Packetery/Checkout/Block/System/Config/Form/ApiKeyValidate.php
+++ b/Packetery/Checkout/Block/System/Config/Form/ApiKeyValidate.php
@@ -9,7 +9,7 @@ class ApiKeyValidate extends \Magento\Framework\App\Config\Value
     private const API_KEY_LENGTH = 16;
 
     /**
-     * @return void
+     * @return self
      * @throws \Magento\Framework\Exception\ValidatorException
      * @throws \Magento\Framework\Exception\FileSystemException
      */
@@ -23,6 +23,6 @@ public function beforeSave()
             throw new \Magento\Framework\Exception\ValidatorException($message);
         }
 
-        parent::beforeSave();
+        return parent::beforeSave();
     }
 }
diff --git a/Packetery/Checkout/Block/System/Config/Form/ApiPasswordValidate.php b/Packetery/Checkout/Block/System/Config/Form/ApiPasswordValidate.php
index d6efba40..dc6f5816 100755
--- a/Packetery/Checkout/Block/System/Config/Form/ApiPasswordValidate.php
+++ b/Packetery/Checkout/Block/System/Config/Form/ApiPasswordValidate.php
@@ -7,7 +7,7 @@ class ApiPasswordValidate extends \Magento\Framework\App\Config\Value
     private const API_PASSWORD_LENGTH = 32;
 
     /**
-     * @return void
+     * @return self
      * @throws \Magento\Framework\Exception\ValidatorException
      */
     public function beforeSave()
@@ -21,6 +21,6 @@ public function beforeSave()
             throw new \Magento\Framework\Exception\ValidatorException($message);
         }
 
-        parent::beforeSave();
+        return parent::beforeSave();
     }
 }
diff --git a/Packetery/Checkout/Controller/Adminhtml/Order/Detail.php b/Packetery/Checkout/Controller/Adminhtml/Order/Detail.php
index e3177036..d3322263 100644
--- a/Packetery/Checkout/Controller/Adminhtml/Order/Detail.php
+++ b/Packetery/Checkout/Controller/Adminhtml/Order/Detail.php
@@ -66,6 +66,7 @@ public function execute(): AbstractResult
             return $this->resultRedirectFactory->create()->setPath('*/*/index');
         }
 
+        /** @var \Magento\Framework\View\Element\AbstractBlock $addressDetailBlock */
         $addressDetailBlock = $resultPage->getLayout()->getBlock('packetery_order_address_detail');
         $addressDetailBlock->setData('order', $order);
         $addressDetailBlock->setData('magentoOrder', $magentoOrder);
diff --git a/Packetery/Checkout/Model/Carrier/AbstractCarrier.php b/Packetery/Checkout/Model/Carrier/AbstractCarrier.php
index 45dc5229..d29163b2 100644
--- a/Packetery/Checkout/Model/Carrier/AbstractCarrier.php
+++ b/Packetery/Checkout/Model/Carrier/AbstractCarrier.php
@@ -39,7 +39,15 @@ public function __construct(
     }
 
     /**
-     * {@inheritdoc}
+     * @return mixed
+     */
+    public function getStore()
+    {
+        return parent::getStore();
+    }
+
+    /**
+     * @return bool|\Magento\Framework\DataObject|\Magento\Shipping\Model\Rate\Result|null
      */
     public function collectRates(RateRequest $request)
     {
diff --git a/Packetery/Checkout/Model/Carrier/Facade.php b/Packetery/Checkout/Model/Carrier/Facade.php
index 526d5165..9423d1a0 100644
--- a/Packetery/Checkout/Model/Carrier/Facade.php
+++ b/Packetery/Checkout/Model/Carrier/Facade.php
@@ -100,7 +100,7 @@ public function createHybridCarrierCached(array &$cache, string $carrierCode, ?i
 
     /**
      * @param \Packetery\Checkout\Model\Carrier\AbstractDynamicCarrier[] $carriers
-     * @return string[]
+     * @return array{value: string, label: \Magento\Framework\Phrase}[]
      */
     public function getVendorCodesOptions(array $carriers): array
     {
@@ -190,12 +190,9 @@ private function getDynamicCarrier(AbstractCarrier $carrier, ?int $carrierId): ?
         return $carrier->getPacketeryBrain()->getDynamicCarrierById($carrierId);
     }
 
-    /**
-     * @param string $carrierCode
-     * @return \Packetery\Checkout\Model\Carrier\AbstractCarrier
-     */
     public function getMagentoCarrier(string $carrierCode): AbstractCarrier
     {
+        // @phpstan-ignore-next-line
         return $this->carrierFactory->get($carrierCode);
     }
 
diff --git a/Packetery/Checkout/Model/Carrier/Imp/Packetery/Carrier.php b/Packetery/Checkout/Model/Carrier/Imp/Packetery/Carrier.php
index 38292e98..9e7d13bb 100644
--- a/Packetery/Checkout/Model/Carrier/Imp/Packetery/Carrier.php
+++ b/Packetery/Checkout/Model/Carrier/Imp/Packetery/Carrier.php
@@ -14,6 +14,9 @@ class Carrier extends \Packetery\Checkout\Model\Carrier\AbstractCarrier
     /** @var \Packetery\Checkout\Model\Carrier\Imp\Packetery\Brain */
     protected $packeteryBrain;
 
+    /** @var \Packetery\Checkout\Model\Carrier\Imp\Packetery\Config */
+    protected $packeteryConfig;
+
     /**
      * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
      * @param \Magento\Quote\Model\Quote\Address\RateResult\ErrorFactory $rateErrorFactory
@@ -31,18 +34,12 @@ public function __construct(
         parent::__construct($scopeConfig, $rateErrorFactory, $logger, $brain, $data);
     }
 
-    /**
-     * @return \Packetery\Checkout\Model\Carrier\Imp\Packetery\Brain
-     */
-    public function getPacketeryBrain(): \Packetery\Checkout\Model\Carrier\AbstractBrain
+    public function getPacketeryBrain(): \Packetery\Checkout\Model\Carrier\Imp\Packetery\Brain
     {
         return $this->packeteryBrain;
     }
 
-    /**
-     * @return \Packetery\Checkout\Model\Carrier\Imp\Packetery\Config
-     */
-    public function getPacketeryConfig(): AbstractConfig
+    public function getPacketeryConfig(): \Packetery\Checkout\Model\Carrier\Imp\Packetery\Config
     {
         return $this->packeteryConfig;
     }
diff --git a/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Brain.php b/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Brain.php
index 9e2116ce..b5dbd24f 100644
--- a/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Brain.php
+++ b/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Brain.php
@@ -78,7 +78,7 @@ public function isAssignableToPricingRule(): bool
 
     /**
      * @param int|null $dynamicCarrierId
-     * @return \Packetery\Checkout\Model\Carrier|null
+     * @return \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\DynamicCarrier|null
      */
     public function getDynamicCarrierById(?int $dynamicCarrierId): ?AbstractDynamicCarrier
     {
diff --git a/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Carrier.php b/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Carrier.php
index 84d1c191..041c7dc2 100644
--- a/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Carrier.php
+++ b/Packetery/Checkout/Model/Carrier/Imp/PacketeryPacketaDynamic/Carrier.php
@@ -14,6 +14,9 @@ class Carrier extends \Packetery\Checkout\Model\Carrier\AbstractCarrier
     /** @var \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Brain */
     protected $packeteryBrain;
 
+    /** @var \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Config */
+    protected $packeteryConfig;
+
     /**
      * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
      * @param \Magento\Quote\Model\Quote\Address\RateResult\ErrorFactory $rateErrorFactory
@@ -31,20 +34,14 @@ public function __construct(
         parent::__construct($scopeConfig, $rateErrorFactory, $logger, $brain, $data);
     }
 
-    /**
-     * @return \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Brain
-     */
-    public function getPacketeryBrain(): \Packetery\Checkout\Model\Carrier\AbstractBrain
+    public function getPacketeryBrain(): \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Brain
     {
-        return parent::getPacketeryBrain();
+        return $this->packeteryBrain;
     }
 
-    /**
-     * @return \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Config
-     */
-    public function getPacketeryConfig(): \Packetery\Checkout\Model\Carrier\Config\AbstractConfig
+    public function getPacketeryConfig(): \Packetery\Checkout\Model\Carrier\Imp\PacketeryPacketaDynamic\Config
     {
-        return parent::getPacketeryConfig();
+        return $this->packeteryConfig;
     }
 
     /**
diff --git a/Packetery/Checkout/Model/Carrier/ShippingRateCode.php b/Packetery/Checkout/Model/Carrier/ShippingRateCode.php
index 91193b21..7affdf8c 100644
--- a/Packetery/Checkout/Model/Carrier/ShippingRateCode.php
+++ b/Packetery/Checkout/Model/Carrier/ShippingRateCode.php
@@ -39,7 +39,7 @@ public static function isPacketery(string $code): bool
 
     /**
      * @param string $rateCode
-     * @return static
+     * @return self
      */
     public static function fromString(string $rateCode): self
     {
diff --git a/Packetery/Checkout/Model/HybridCarrier.php b/Packetery/Checkout/Model/HybridCarrier.php
index 5f22c2a2..6a1a4229 100644
--- a/Packetery/Checkout/Model/HybridCarrier.php
+++ b/Packetery/Checkout/Model/HybridCarrier.php
@@ -39,7 +39,7 @@ public static function fromAbstractDynamic(\Packetery\Checkout\Model\Carrier\Abs
      * @param string $method
      * @param string $country
      * @param array $vendorCodeOptions
-     * @return static
+     * @return self
      */
     public static function fromAbstract(\Packetery\Checkout\Model\Carrier\AbstractCarrier $carrier, string $method, string $country, array $vendorCodeOptions): self
     {
diff --git a/Packetery/Checkout/Model/ResourceModel/Carrier/Collection.php b/Packetery/Checkout/Model/ResourceModel/Carrier/Collection.php
index cf67d3ee..3b46c565 100644
--- a/Packetery/Checkout/Model/ResourceModel/Carrier/Collection.php
+++ b/Packetery/Checkout/Model/ResourceModel/Carrier/Collection.php
@@ -25,6 +25,7 @@ protected function _construct()
      */
     public function getItems()
     {
+        // @phpstan-ignore-next-line
         return parent::getItems();
     }
 
diff --git a/Packetery/Checkout/Model/ResourceModel/Order/Collection.php b/Packetery/Checkout/Model/ResourceModel/Order/Collection.php
index 8b5f82ad..6900e12c 100755
--- a/Packetery/Checkout/Model/ResourceModel/Order/Collection.php
+++ b/Packetery/Checkout/Model/ResourceModel/Order/Collection.php
@@ -18,6 +18,15 @@ protected function _construct()
         $this->_init('Packetery\Checkout\Model\Order', 'Packetery\Checkout\Model\ResourceModel\Order');
     }
 
+    /**
+     * @return \Packetery\Checkout\Model\Order[]
+     */
+    public function getItems()
+    {
+        // @phpstan-ignore-next-line
+        return parent::getItems();
+    }
+
     /**
      * @return string
      */
diff --git a/Packetery/Checkout/Model/ResourceModel/Pricingrule/Collection.php b/Packetery/Checkout/Model/ResourceModel/Pricingrule/Collection.php
index a4ead75b..9ab4cd0a 100644
--- a/Packetery/Checkout/Model/ResourceModel/Pricingrule/Collection.php
+++ b/Packetery/Checkout/Model/ResourceModel/Pricingrule/Collection.php
@@ -28,6 +28,7 @@ protected function _construct()
      */
     public function getItems()
     {
+        // @phpstan-ignore-next-line
         return parent::getItems();
     }
 
@@ -37,6 +38,7 @@ public function getItems()
     public function getFirstRecord(): ?\Packetery\Checkout\Model\Pricingrule
     {
         $this->load();
+        /** @var \Packetery\Checkout\Model\Pricingrule[] $items */
         $items = $this->_items;
 
         return array_shift($items);
diff --git a/Packetery/Checkout/Model/ResourceModel/PricingruleRepository.php b/Packetery/Checkout/Model/ResourceModel/PricingruleRepository.php
index 5ed256f8..ba563d3f 100644
--- a/Packetery/Checkout/Model/ResourceModel/PricingruleRepository.php
+++ b/Packetery/Checkout/Model/ResourceModel/PricingruleRepository.php
@@ -203,9 +203,11 @@ public function savePricingRule(array $postData, array $weightRules): \Packetery
      */
     public function setPricingRuleEnabled(int $id, bool $enabled): void
     {
-        $rule = $this->pricingRuleCollectionFactory->create()->getItemById($id);
-        $rule->setData('enabled', $enabled);
-        $rule->save();
+        /** @var \Packetery\Checkout\Model\ResourceModel\Pricingrule\Collection $collection */
+        $collection = $this->pricingRuleCollectionFactory->create();
+        $collection->addFilter('id', $id);
+        $collection->setDataToAll('enabled', $enabled);
+        $collection->save();
     }
 
     /**
diff --git a/Packetery/Checkout/Model/ResourceModel/Weightrule/Collection.php b/Packetery/Checkout/Model/ResourceModel/Weightrule/Collection.php
index eb3d7692..c475af5d 100644
--- a/Packetery/Checkout/Model/ResourceModel/Weightrule/Collection.php
+++ b/Packetery/Checkout/Model/ResourceModel/Weightrule/Collection.php
@@ -28,6 +28,7 @@ protected function _construct()
      */
     public function getItems()
     {
+        // @phpstan-ignore-next-line
         return parent::getItems();
     }
 }
diff --git a/Packetery/Checkout/Model/Weight/Calculator.php b/Packetery/Checkout/Model/Weight/Calculator.php
index 9340d2bb..f6f963d3 100644
--- a/Packetery/Checkout/Model/Weight/Calculator.php
+++ b/Packetery/Checkout/Model/Weight/Calculator.php
@@ -32,7 +32,6 @@ public function getItemsWeight(array $allVisibleItems): float
 
         foreach ($allVisibleItems as $item) {
             if ($item->getProductType() === 'configurable') {
-                /** @var \Magento\Catalog\Model\Product $configurableProduct */
                 $configurableProduct = $item->getProduct();
                 if ($configurableProduct->isVirtual()) {
                     $configurableWeight = 0.0;
@@ -40,10 +39,8 @@ public function getItemsWeight(array $allVisibleItems): float
                     $configurableWeight = $configurableProduct->getWeight();
                 }
 
-                /** @var Item[] $children */
                 $children = ($item->getChildren() ?: []); // contains only ordered items
                 foreach ($children as $child) {
-                    /** @var \Magento\Catalog\Model\Product $childProduct */
                     $childProduct = $child->getProduct();
                     if ($childProduct->isVirtual()) {
                         $productWeights[$childProduct->getId()] = 0.0;
@@ -62,7 +59,6 @@ public function getItemsWeight(array $allVisibleItems): float
         }
 
         foreach ($allVisibleItems as $item) {
-            /** @var \Magento\Catalog\Model\Product $product */
             $product = $item->getProduct();
             if ($item->getProductType() === 'simple' && !array_key_exists($product->getId(), $productWeights)) {
                 if ($product->isVirtual()) {
diff --git a/Packetery/Checkout/Model/Weight/Item.php b/Packetery/Checkout/Model/Weight/Item.php
index f51491fd..f781e4c6 100644
--- a/Packetery/Checkout/Model/Weight/Item.php
+++ b/Packetery/Checkout/Model/Weight/Item.php
@@ -29,7 +29,7 @@ public static function transformItems(array $items): array
 
     /**
      * @param \Magento\Quote\Model\Quote\Item $item
-     * @return static
+     * @return self
      */
     public static function fromQuoteItem(\Magento\Quote\Model\Quote\Item $item): self
     {
@@ -49,7 +49,7 @@ public static function fromQuoteItem(\Magento\Quote\Model\Quote\Item $item): sel
 
     /**
      * @param \Magento\Sales\Model\Order\Item $item
-     * @return static
+     * @return self
      */
     public static function fromOrderItem(\Magento\Sales\Model\Order\Item $item): self
     {
@@ -66,4 +66,36 @@ public static function fromOrderItem(\Magento\Sales\Model\Order\Item $item): sel
 
         return $instance;
     }
+
+    /**
+     * @return string
+     */
+    public function getProductType()
+    {
+        return parent::getProductType();
+    }
+
+    /**
+     * @return self[]
+     */
+    public function getChildren()
+    {
+        return $this->getData('children');
+    }
+
+    /**
+     * @return int
+     */
+    public function getQty()
+    {
+        return $this->getData('qty');
+    }
+
+    /**
+     * @return \Magento\Catalog\Model\Product
+     */
+    public function getProduct()
+    {
+        return $this->getData('product');
+    }
 }
diff --git a/Packetery/Checkout/Observer/Sales/AddressPlaceAfter.php b/Packetery/Checkout/Observer/Sales/AddressPlaceAfter.php
index 4dc9324f..8b75a640 100644
--- a/Packetery/Checkout/Observer/Sales/AddressPlaceAfter.php
+++ b/Packetery/Checkout/Observer/Sales/AddressPlaceAfter.php
@@ -29,6 +29,7 @@ public function execute(
         \Magento\Framework\Event\Observer $observer
     ) {
         $orderId = $observer->getData('order_id');
+        /** @var \Magento\Sales\Model\Order $order */
         $order = $this->orderRepository->get($orderId);
         $orderNumber = $order->getIncrementId();
         $shippingAddress = $order->getShippingAddress();
diff --git a/Packetery/Checkout/Observer/Sales/EmailOrderTemplateVarsBefore.php b/Packetery/Checkout/Observer/Sales/EmailOrderTemplateVarsBefore.php
index b538b954..1066072e 100644
--- a/Packetery/Checkout/Observer/Sales/EmailOrderTemplateVarsBefore.php
+++ b/Packetery/Checkout/Observer/Sales/EmailOrderTemplateVarsBefore.php
@@ -37,8 +37,8 @@ public function execute(\Magento\Framework\Event\Observer $observer)
         $order = $transport['order'];
         $collection = $this->orderCollectionFactory->create();
         $collection->addFilter('order_number', $order->getData('increment_id'));
-        /** @var \Packetery\Checkout\Model\Order|null $packeteryOrder */
         $items = ( $collection->getItems() ?: [] );
+        /** @var \Packetery\Checkout\Model\Order|null $packeteryOrder */
         $packeteryOrder = array_shift($items);
 
         $transport['packetery_is_pickup_point'] = false;
diff --git a/Packetery/Checkout/Ui/Component/CarrierCountry/Listing/SearchResult.php b/Packetery/Checkout/Ui/Component/CarrierCountry/Listing/SearchResult.php
index 4b2ffcc4..6d166e97 100644
--- a/Packetery/Checkout/Ui/Component/CarrierCountry/Listing/SearchResult.php
+++ b/Packetery/Checkout/Ui/Component/CarrierCountry/Listing/SearchResult.php
@@ -79,7 +79,5 @@ protected function _initSelect()
             );
 
         $this->addFilterToMap('availableName', 'available');
-
-        return $this;
     }
 }
diff --git a/Packetery/Checkout/Ui/Component/Order/Listing/SearchResult.php b/Packetery/Checkout/Ui/Component/Order/Listing/SearchResult.php
index 0c90d8b0..e5ba3928 100644
--- a/Packetery/Checkout/Ui/Component/Order/Listing/SearchResult.php
+++ b/Packetery/Checkout/Ui/Component/Order/Listing/SearchResult.php
@@ -79,7 +79,5 @@ protected function _initSelect()
                     'main_table' => new Expression('(' . $subQuery->assemble() . ')'),
                 ]
             );
-
-        return $this;
     }
 }
diff --git a/Packetery/Checkout/view/adminhtml/templates/order-address-detail.phtml b/Packetery/Checkout/view/adminhtml/templates/order-address-detail.phtml
index b03a840d..7198fedc 100644
--- a/Packetery/Checkout/view/adminhtml/templates/order-address-detail.phtml
+++ b/Packetery/Checkout/view/adminhtml/templates/order-address-detail.phtml
@@ -1,5 +1,5 @@
 <?php
-/** @var \Packetery\Checkout\Block\Adminhtml\Order\AddressDetail $block */
+/** @var \Magento\Framework\View\Element\AbstractBlock $block */
 /** @var \Packetery\Checkout\Model\Order $packeteryOrder */
 $packeteryOrder = $block->getData('order');
 $packeteryMagentoOrder = $block->getData('magentoOrder');
diff --git a/phpstan-config.neon b/phpstan-config.neon
index 25b4846c..f694b285 100644
--- a/phpstan-config.neon
+++ b/phpstan-config.neon
@@ -1,9 +1,12 @@
 parameters:
     bootstrapFiles:
         - phpstan-autoload.php
-    level: 1
+    level: 3
     fileExtensions:
         - php
         - phtml
     paths:
         - ./Packetery/Checkout
+    ignoreErrors:
+        - '#Call to an undefined method Magento\\(.*)+\(\)\.#' # It is typical for Magento related code to use PHP magic.
+        - '#Call to an undefined static method Magento\\(.*)+\(\)\.#'