FWIW I’ve migrated my laptop to /gnu/store, and also switched to a different $localstatedir (meaning that the store’s DB, build log directory, profiles, etc. are stored in a different place.)
After that, I ended up starting from an empty profile (because the old one was elsewhere.) So I recreated my profile with: guix package -i $(guix package -I . \ -p /nix/var/nix/profiles/per-user/ludo/guix-profile | \ cut -f1,3 | sed -e's/\t/:/g') where /nix/var/../guix-profile is the old profile. Ludo’.