The only machine you wanna be using SteamOS on is the Steam Deck. Use a standard Linux distribution like Ubuntu if you’re gonna do it on any other machine. The reason being that the version of SteamOS for generic PCs is horribly outdated, and the one on the Deck is very much built exclusively for the Deck’s hardware.

Gaming mostly works out of the box with almost all games on Steam on Linux (SteamOS is not special in this regard) but there is an important caveat; be careful of games that use anticheat software - some work but others do not or may trigger bans. Check ProtonDB for your specific games to see if there are issues.