Related question: does anybody exclusively use any Linux distro on MacBooks in a VM? What is the tradeoff and how is your experience?

I want the MacBooks for the battery backup, but I cannot live without NixOS, and seems like Asahi is still a few months away.

One of the most popular NixOS configs on GitHub does this https://github.com/mitchellh/nixos-config

The README describes the experience, though the author takes the approach of using the VM mainly for terminal-based stuff.