I completely agree. I'm also trying to wrap my head around Nix on a non-NixOS system. My requirements are to just manage my dotfiles (successful with home-manager) and configuring my system/installing certain packages, so everyone on the host can e. g. start a docker container with Docker installed by Nix. Ideally all with flakes.

I suppose, I can't have the second part without NixOS, though ...