OK, at the risk of "just go vibe code it yourself": I really think that Nostr needs to do more with the #fediverse bridges (i.e. Mostr, Momostr, others?). There needs to be some mechanism or signal to say that, when you comment, that comment will (probably) make it back to the Mastodon instance the original post came from.
Otherwise, what's the point? It's just like an RSS feed reader or something, but worse, because it gives the _illusion_ of 2-way communication when it's really just 1-way.