I strongly also think we're going to have a social network for humans-only (and one for AI-only, and one for humans + AI)

have you looked into world.org? They're scanning eyes and giving robust human identities. Before immediately dismissing, I'd check out the video -- https://www.youtube.com/watch?v=SXnwoMxKHV8

I think atproto + worldid can one day be very interesting