Just an update on this. Indeed the relay list was empty on Primal, even though other apps have no issue fetching it. So upon updating it on the web client the app now works flawlessly.

What confused me with the relay page was that the section in the middle was empty (cause there was no relays set) so my focus went to the relay list on the right, which I thought was the actual list, not a fallback list (which is what I assume it is since there was no relay set in the proper section).

Plus Primal seems to have an issue populating the middle section automatically if the account/keys pair was created on another client. I confirmed this by creating new keys on both Primal and other clients, then testing them both on the Primal Android app.

TLDR; network settings page was confusing, adding relays to the correct section solved the issue.