I made Kubuntu my main OS a long time ago, and I play a lot of (thanks to Valve, Steam, Wine and Proton...) games, and I never experienced a game freezing. My experience it's so good, that I only touch Windows to play Fornite.

The only annoying bug/problem that I have actually, it's that Dolphin could have a erratic behavior if I had mounted a SMB folder via an VPN and I end the VPN before un-mounting the SMB folder.