this article actually served as a great Nix tutorial, and (having stepped away from Nix after getting burned with NixOS) I think I'll try it again since the author is still encouraging NixOS for the server edition on RaspBerry Pi's
Author here, NixOS is not for the faint of heart, not even on a server. With that said, if you understand it well, it is much easier in my opinion. It's a lot like typed languages, harder to get stuff done, but much more solid after the fact.