@zenithseeker @nostupidquestions
ActivityPub have supports for multiple type of objects, and actions on those objects. Like liking (or upvoting) a post.
But beside that, it’s just about the same. You can absolutely build a functioning bridge that would translate emails into ActivityPub and then subscribe to it from Lemmy instance. There are a lot of bridges (XMPP, Twitter mirrors, Nostr, etc.)