What is your reasoning behind nr.3? I don’t disagree as they seem hostile towards the nix HA project. At least that is what I gathered when I set up my zigbee devices on a NixOS server.
There are parts of NixOS that require specific support or you apps simply don’t work, and I can see why a developer would not want NixOS issues causing tickets for them.
IIRC they didn't want distributed via any package manager (apt, yum &c.); nixpkgs was not singled-out[1]. This was a while ago, so I may have misremembered.
1: Though NixOS users have both social and technical reasons for more strongly wanting software to be in nixpkgs than e.g. Ubuntu users have for wanting the software to be distributed via apt.
I'm not sure NixOS users are that different from users of other distros, all want a tool that properly manages their systems (rather than random packages being scattered everywhere).
1. Zigbee devices are crazy inexpensive. I can get two zigbee power switches for less than half the cost of a single USB controlled one.
2. Zigbee2Mqtt is really nice; setting it and mosquitto up was easy, and I can control everything over mqtt now.
3. The creator of HA really doesn't want me using his software, so I'm not.