I use #rde to declare my entire init.el within my home-configuration.scm. it's not the most efficient (probably because I don't take advantage of any of the rde-specific features that provide greater feature modularity), but it's fun to have your entire personal computing setup in a single emacs-style file:
https://git.sr.ht/~reproducible/.guix/tree/trunk/item/home-configuration.scm#L363