I'm also using X11 w/ KDE as Wayland has broken Synergy, which I need.
Is it frozen completely, or is it just the mouse click isn't working right? I have a problem that I've had since upgrading to F34 where my mouse randomly won't click consistently. From my testing its getting stuck in the focus of one window and can't get out.
The keyboard doesn't have this issue, try pressing the menu key on your keyboard whilst you are moused over the desktop. Does the context menu come up then?
The only fix I've found for my issue is to log out, then log into another dummy account. Then I can log back out and back into mine and it works fine.
Cheers,
Ayden