You mostly seem bent on dissing nostr. But you do have a point. Only the strfry relays have a sync protocol to gossip messages between relays similar to scuttlebutt. We also do have a discovery problem mapping which npubs have content on which relays. Some relays have bots attached to them which look up profiles and relay lists, this is how purplepag.es, relay.nos.social, and primal do it. I think some sort of DHT to map users to relay is needed to prevent centralization of relays. 

That said, it’s a hell of a lot better than ActivityPub which puts all power for identity, content, privacy, and connections in to the hands of single instances. What’s more AP claims it’s interoperable but it’s not really. I can’t use my mastodon.social account to manage my events on a mobilizon events server. If i want to use peertube, again i’ll need a new account, followers, content, etc…. Sure they’re all ActivityPub and part of the fediverse, but it’s kind of like parallel universes, they don’t benefit from each other.