I use a steam deck for about 2/3 of my gaming and I rarely have issues with games. That said, I mostly play indie games, but there is so much of my library that is supported that I’m never going to run out of things to play. Proton has really done wonders for gaming on Linux. Are you wanting to play multiplayer games or brand new releases? Or are you more of the patient gamer type?
I wouldn’t run steamos on a full desktop, but you can still get a lot of the benefits just by using steam on Linux. Definitely recommend trying it out.