It's really only the (crucial) segment of big, trendy multiplayer titles where support is still really hit-and-miss. If gaming is essential to your social network, Linux may not be ready for you to entirely switch over.
But if you're someone whose social hobbies lie elsewhere who enjoys solo gaming, there are way more excellent Linux games ready for you to enjoy than there is time for you to play them.
I was disappointed when post-purchase Psyonix dropped official Linux support for Rocket League. However, the Proton support has been rock solid, and I'm yet to encounter any crashes, even after updates. The Linux binaries occasionally had regressions after an update.
From memory, Valve has also been supporting anti-cheat providers to port to Linux (or perhaps I have misunderstood and they will also run under Proton?), so there’s always a chance this will be solved in the next couple of years. The Steam Deck has been a great catalyst for that within Valve, it seems.
I think if, over time, it looks like those fears are unfounded and there are few practical problems with anti-cheat for competitive games on Linux, then probably some currently-hesitant publishers will relent and enable their games on Linux. But only time will tell, I suppose.
Not really a gamer. Cyberpunk is probably my high water mark at 90 hours. It's so nice to not to have to make major concessions to run Linux.
Valve you have earned a customer with me.