Hello!

I'm new to Linux. I've installed KDE Neon 5.12 yesterday and i try to disable compositor using alt+shift+f12 whenever i launch a game on wine for performance. However, sometimes KDE just stops working properly when i disable compositor. Dolphin works fine, but super key (app launcher) and the panel in general just stops working, i can't even maximize and minimize the applications using the panel, i have to log out and log in again to be able to use KDE again.

Instead of manually disabling and enabling compositing, you should try using the Block Compositing Window Rules.

Create a new kwin application rule for the game: Either right-click on the title-bar of the game -> More Actions -> Special Application Settings, or go to System Settings -> Window Management -> Window Rules -> New and fill in the necessary matching. At the bottom of the last tab, check the option to Block Compositing.
With this option enabled, Kwin should suspend compositing while the game is running and resume when you close it.

More technical details are available on Martin Grasin's blog post on the subject (about 1/2-way down, under Removal of unredirect fullscreen windows, in particular the last two paragraphs of that section): https://blog.martin-graesslin.com/blog/ ... mpositing/