day-to-day management would involve also learning about guix home which is analogous to Nix's home manager. Don't be too afraid of the Guix manual and always make sure you're using the latest one.

If you seriously want to use Guix you basically have to become a contributor since the project is still in its infancy (Nix is over 20 years old by comparison and only recently got popular). I recommend subscribing to the Guix-devel and Guix-help mailing lists as well. Guix is highly rewarding since it's a vision into a reproducible, libre future that has never been tried before in human history but if you want to use an immutable system on a production machine I'd recommend Nix.