For some reason, when I try to enable fullscreen in an XWayland game it just glitches out. It works perfectly when windowed, but when enabling fullscreen the window completely disappears, while still showing on the taskbar and alt-tab menu as active. On X11, fullscreen works without issue.

I tried with both Celeste (Wine) and Minecraft (Native); both running on OpenGL. I'm running Plasma on Wayland, configured with Pipewire. The only "related" modification I did was installing the flatpak version of XWayland-video-bridge once, but I have removed it since.

System:
Operating System: Solus 4.4
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.106.0
Qt Version: 5.15.9
Kernel Version: 6.3.6-239.current (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-7200U CPU @ 2.50GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 620

This same thing happens when I try to take a VM to full-screen when the host is running on Wayland. I've already filed a bug report for that, but it might get triaged a bit higher if you report that it also affects gaming.

    Zenurik Have you reported it on KDE's bug tracker?

    No, just just mentioned it in the KDE forum first, to see whether anyone there had noticed it. I reported it to the Solus bug tracker, but wanted to make sure it wasn't a Solus-only problem first before asking the KDE devs to deal with it. No one has yet responded at KDE, so I believe it might be ours only. Wayland is fairly new here, but it's old stuff for KDE.