I've been on NixOS for a little over a year, and have been absolutely delighted at how well gaming works now. I initially thought I would dual boot until Windows 10 EoL, but have had no reason to use Windows in that time and a couple months ago I converted my storage disk from ntfs to ext4.

Steam is nearly seamless; there have been one or two titles where I've had to switch the Proton version to experimental or GE, but nothing more than that. Heroic and Lutris have been similarly easy for non-Steam games. There has been nothing that I have tried to play that hasn't worked, but I don't play multiplayer games so YMMV there.

That said, this is not my first rodeo with Linux. I used it extensively in the late '00s and early '10s, which probably helped to sand some of the rough edges off of my recent experience. Though back then wine was not really suitable for gaming. I also have an AMD GPU, which I understand has an easier setup process than Nvidia. (I literally haven't had to think about graphics drivers at all.)