There isn't a GUI (although nix-gui [1] is in progress) but there is a very good and decently mature flake template called Devos [2] for accomplishing most of what you ask. It basically lets you write very simple profiles to group configuration settings together and then you can assign those profiles to machines or users.
Things could still be improved but I found Devos to be good enough that NixOS is usable for personal and even some production use.
Once I get around to it, I'll move/mirror my configs to Github which should serve as good examples.
Things could still be improved but I found Devos to be good enough that NixOS is usable for personal and even some production use.
Once I get around to it, I'll move/mirror my configs to Github which should serve as good examples.
[1] https://github.com/nix-gui/nix-gui [2] https://github.com/divnix/devos