NixOS’s documentation is dog. It’s not absolute dog, but it’s dog. The learning curve is brutal.
But… the (mostly) declarative management is its strongest feature. It’s very solid and you can easily unfuck you system if you haven’t done stuff like mess with partitions or delete files manually.
If NixOS had better documentation and GUI to manage the system, it would be a no-brainer, but unfortunately, it is about 5-10 years away from that. The community is very top heavy, but it’s easy to just do your own stuff.