Dear Maintainer,

this probably happens on laptops with a integrated Intel GPU and a
dedicated NVidia GPU. The XServer is running using the integrated GPU.
However, when using the dedicated GPU to run a graphics intensive
application (like a game) in fullscreen mode the whole XServer freezes
after some time (varies randomly between applications - could be almost
immediately after application was started or several minutes). It is
possible to login via ssh and restart the sddm service or reboot the
machine via the magic SysRq key. Audio can be heard and the mouse screen
is still visible and can be moved. Apart from that it seems it is
completely unresponsive.
This bug probably exists upstream aswell:
https://gitlab.freedesktop.org/xorg/xserver/-/issues/24

Cheers,
Andrej