I use Lazygit, which is a TUI. It is entirely controlled by keyboard shortcuts and has a lot of quick ways to do tedious things.

Important to note that NixOS has both a rolling release and point release version.

A simple bash script is not reproducible or deterministic. Also a filesystem rollback is not the same as NixOS’s generation based rollback.

Also, NixOS doesn’t just install packages, all system configuration is done declaratively, which would be a very bad idea to do via a bash script.