I don’t know why but every now and then my display completely freezes, completely except my mouse which is still able to navigate the screen, but can’t interact with anything. No hotkey works, seems that the keyboard freezes too when this happens, except for the one that lets me enable the leds of the pc. I use a msi laptop with hybrid graphics card if that can help
Similar thing sometimes happens to me on my ThinkPad. I have KDE Plasma and X11 (will switch to Wayland when Plasma 6 is out). Also, sometimes the exact opposite thing happens, when my mouse is frozen, but I can interact with my system using keyboard (switching wirtual desktops and windows, typing and executing commands in terminal,…) and it all works except the mouse. It's pretty rare, however. It happened few times after waking up from hibernation or sleep, but it happend even without that. Good luck with finding solution, maybe switching to Wayland will help if you'reon X11 like me.
If i switch to wayland my hybrid graphics card won't work and i can't play games like i normally would on X11. Btw the solution was switching distro, as usual. Every time there's something fucked up i just switch distro.