I've been gaming on Linux for a few years now and it runs anything I've picked without issues (even bigger stuff like Baldurs Gate 3). In fact I'm surprised how smooth and trouble free the experience is.
Linux is pretty much flawless for single player gaming at this point.
Linux is pretty freaking good for a good chunk of MMO's and multiplayer games, too.. But you have to approach these games with caution and research to make sure the one you are interested in doesnt have invasive rootkit anticheats.. cause those games wont work on linux, and thats entirely because of the game dev's choices, not a linux issue.
I mean, it runs everything I need. But what is mainstream gaming to everyone else? Is it fortnite? Call of duty? Destiny 2? Pubg? Valorant? GTA? Battlefield? (weirdly a lot of shooters), Apex? Siege?
May not matter to people like us but they each command something to the effect of hundreds of thousands of concurrent players. Capable as Linux distros are for gaming (truly the best way to experience classic games) the anticheat situation is no less dire.
Linux is ready for mainstream gaming right now. Mainstream gaming doesn’t like it because they see Windows users as dumb money bags, and Linux users as annoying freeloaders. That’s not true, but that’s the general sentiment in a bunch of execs. That’s why anticheat is available for Linux, but companies refuse to enable it.
Sim Racing is one of the reasons I am still on windows. I can play most of my games nicely with Linux, but I spend a huge chunk of time racing in the evening. And it is just very hit and miss, and hardware can be a bit of a pain.
Unfortunately it is easier to just stay in windows than reboot every time I want to play something else.