The official user docs are quite unhelpful for newcomers. They’re not introductions but rather manuals for system administrators.

nix-env should be deprecated and home manager should be promoted more but the governance around Nix can be fragmented. Home manager is like your configuration.nix but per user rather than per machine.

Nix’s error logs can be very cryptic which is why you should always edit nix files with a syntax checker. Usually what you want is in the middle of the backtrace.

I’ve been using NixOS for a month or so and it has been an incredible experience, but it’s not meant for everyone. If you want fearless updates you can use Fedora Atomic Desktop.