I wonder if this is relevant/helpful: https://itsfoss.com/systemd-sysext/

Newer instructions by the same author: http://sam-d.com/blog//running-guix-package-manager-on-top-of-fedora-silverblue-updated-instructions/

Toolbox/distrobox instructions: https://forum.systemcrafters.net/t/guix-on-fedora-silverblue-anyone/2033