I had issues with cs:go lately as well. The game freezes when I do not move the mouse.
The issue was caused by a recent update of libx11 (upgraded libx11 (1.8.2-2 → 1.8.3-1). Donwgrading to version 1.8.2-2 solved the issue for me. Just this morning we received another update to 1.8.3-3. But I dont know if that fixes it as well.
In the meantime I moved to the flatpak version of steam. That does not have an issue.