My thoughts exactly. Apple is a public company, they're not investing in software that'll put money in other companys' pockets.
If you look at what was also announced, it reads pretty clearly as they needed a solution for porting to and developing for their new VR headset.
From your post I think you've got enough of a power user inclination to reccommend Arch. Depending on how quickly you need a system up don't be afraid of trying one of it's derivatives such as endeavor, but there's tons of good guides and documentation in the arch eco system that a technically inclined person should definitely be able to swim. From my experience starting with Manjaro (wouldn't reccomend now) and quickly swapping to Arch, it's very doable and a good way to learn how parts of your operating system interact.
My NixOS install games as well as my Arch one does. Actually better than it since the latest Steam UI update.
I'd definitely recommend against starting with NixOS. Learning resources are way more sparse than something like Arch. Things like the division with flakes and the fact that everyone sets up their configuration differently means that finding examples that work in your config when you're starting out is even harder. Combined with learning how to setup a Linux system is too much for a beginner imo.
If OP is really interested in Nix they should install the Nix package manager on another working Linux installation so they can learn at their own pace.
Ez dev shells
Home Manager + Stylix
Rollbacks
Nutritional yeast, chicken salt, and ghee for the oil is my go to. Absolutely delicious.
NixOS