"Just" write your own module?

Have you seen how bad the Nix documentation is and how challenging Nix (the language) is? Not to mention that you have to learn Yet Another Language just for this corner case, which you will not use for anything else. At least Guix uses a lisp variant so that some of the skills you gain are transferable (e.g. to Emacs, or even to a GP language like Common Lisp or Racket).

Don't get me wrong, I love the concept of Nix and the way it handles dependency management and declarative configuration. But I don't think we can pretend that it's easy.

The documentation is not great (especially since it tends to document nix-the-language and not the conventions actually used in Nixpkgs), but there are very few languages on earth with more examples of modules than Nix.

I’ve never seen nix, but I’d rather learn “yet another language” than fight yet another yaml syntax.