Will pep handle key exchanging as well? Looks interesting, but I can't find out if/how it handles this?
That's kind of a TOFU (Trust On First Use) approach, but you can verify trust by comparing the fingerprints, in p≡p by default represented as dictionary words in your natural language (somewhat similar to Signal). That's suitable for comparison by phone (=> quickly done).
Cf. the documentation for screenshots how this looks (nowadays): https://prettyeasyprivacy.com/docs