Sorry about your troubles. Keep at it, I promise its greener on the other side.
One tip: nix-env installs things ad hoc. Its against fhe whole philosphy of nix, where your system state is defined in files. So don't ever use that. If you need any generic package, you can add it to environment.systemPackages. If you accidentally installed something that way, its okay. Just know you might get an error if you try installing it both from nixos-rebuild and nix-env. If that happens, just uninstall from nix-env.
Do you prefer the track ball for your thumb or for your middle finger?