Point 4 is what lost me when I tried using NixOS for a machine I explicitly wanted as reproducible as possible. I needed to get a bunch of stuff working, then freeze/bundle/lock the useland as a documented working state I could rebuild later if anything went wrong.

When documented examples began steering me towards the still experimental nix flakes and using the sorts of with ever more flags required commands, I bailed and built it using salt. I want to like nix but the current state of things was a massive put off.