I'm doing this with NixOS and too, it was really simple. NixOS unstable hasn't been problem free though, it breaks quite often in the unstable channel, most usually though I just roll the channel back and wait it out. Right now I'm stuck with kernel 5.12 because nvidias shit Linux driver support.

I don't suppose you have a nix file to share? :)

These days many AAA games work well in Gentoo thanks to Proton, though I still dual boot (to Windows 7...) for a lot of games. Looking Glass is pretty cool, though perhaps it's a bit too late. My next Windows on a new computer will be either 10 Enterprise LTSC or 11 if 11 doesn't suck, but I still plan to run Gentoo as my primary. If your NixOS experience matches your expectations over the next year, it'd be neat to hear about it later -- I looked at Nix a long time ago but I've been a happy Gentoo user since 2007 and I still see no reason to move. I've gotten a bit old, but the maintenance is low, every time I use another distro it inevitably annoys me for not being like Gentoo, and anyway the upkeep sort of feels like gardening, not like a pain in the butt.

Just FYI, Looking Glass has been in development for over three years now, so it's not actually as late as you think :).

Also proton doesn't address the myriad of productivity applications that people still need windows for, such as Adobe products, or Autocad, etc.

My windows boot is generally low maintenance, but a Windows update did introduce a stutter in all games once, so had to do a clean install (no restore point). Was annoying to troubleshoot. Windows is a mess. If only anti cheats worked on Linux.

In the Steam Deck announcement this week Valve mentioned they were going to work with vendors to get anti-cheat finally working, so fingers crossed.

I guess it's inevitable. It makes no sense for Windows to be the PC gaming platform; it's only inertia.

It makes sense for almost every user and developer, due to better graphics support from GPU vendors and from Microsoft for Windows.

Well of course, but that's only popularity and inertia. There's no technical reason to prefer Windows over Linux as a gaming platform.

Edit: oh, I just rephrased grandparent comment, sorry.

Better technical support of GPU vendors for games isn't a technical reason?

No, that's logistics. Logistics is relatively easy to change.