1. *nix problems, including bsd including darwin.

2. nix is just package manager and configurator of sh which forces to write idempotent sh code with explicit dependencies(just good practices right? check guidelines of any non nix solutions and you will find out that 90% of these rules are just nix). nixos, nix darwin, nix home manager final artifacts are just just idiomatic dotfiles, so nix does not exist.