i say "magic" because my system config specifically looks for modules in /etc/guix-config/modules...
..but actually, i guess once the system is configured, it probably doesn't need to deal with the configuration file anymore...? this is probably something i should know by now but, well, i don't! lol
aha, and as for sops, i see that the sops files get added to /gnu/store too. okay, that makes sense.
this is all how it's supposed to be, of course... i mean, guix systems are supposed to have things like this in the store.