Font preview is very slow

[Sunspark-007]

Hi, I observed that going into the font selector runs very slowly because it previews the fonts but there are multiple issues present with it.

1. It doesn't actually populate the entire list of fonts present, so you still need to type in the name of the font to make it appear in the pane if it didn't initially show up.
2. Tied to 1 above, typing in the search box the app struggles to keep up with the keypresses, you have to type very slowly otherwise it will miss the key presses or display them out of order or repeat them, likely missing inputs as well.
3. The system benchmark scored 1.76 (4-core system) but if live captions is running and while it is displaying text you go into font preview/select the little red speed icon in the lower right shows up because it doesn't have enough CPU anymore to do both.

I don't know what the issue here is that it struggles with displaying fonts, but a possible workaround might be to have a checkbox to not display font previews in the list.

This is on KDE Plasma.