Not arguing for Nix here, but couldn’t you use Distrobox on Nix to mitigate some of the author’s problems while still getting benefits from Nix for the basic install?
Note: I’m not a Nix user - primarily Fedora and Debian, though I’ve used Bluefin a lot and used to use PopOS as a gaming desktop. (Rarely have any time for gaming these days…)
As a regular user of NixOS and distrobox: Yes, you absolutely can combine them. I actually ended up using distrobox a lot less than planned (native NixOS ended up being friendlier than expected), but it does work.
Note: I’m not a Nix user - primarily Fedora and Debian, though I’ve used Bluefin a lot and used to use PopOS as a gaming desktop. (Rarely have any time for gaming these days…)