I don't use nix-env or home-manager. On my NixOS workstation everything (outside of nix-shells) is installed via environment.systemPackages. And I do wish there was an easy way to add stuff to install packages without rebuilding the whole system - I guess that's what nix-env is for but if I went with that I would the "single editable config file that you can put in VCS" aspect. I think nix-env uses profiles, which are implemented collection of symlinks to the Nix store - guess I could still version those...?
You can define a package that contains a bunch of other things, e.g. I use packages like 'devCli', 'netGui', etc. (I actually put these in my systemPackages on NixOS and nix-darwin, but they would also work with nix-env)
