NixOS is super easy. It gets a bit complicated when you use flakes, but you don’t need to to start.
You just put the system packages into the configuration so you can replicate that system everywhere.
But if you don’t care, just install everything to the user profile! It just works like any distro then, no config files to mess with
The first power spike you will experience is actually setting up a service like Jellyfin by just editing the configuration.nix, though. It’s so much easier than having to mess with the configuration yourself (someone already did the work for you)