https://mostr.pub/  and  https://momostr.pink/ are good for breaking the barriers between Nostr and "Mastodon"

I was able to talk to Nostr from ActivityPub
 

 Yes those are the two bridges but the mastodon side blocked Nostr mostly  

 Mastodon is German, there is no free speech in Germany 

 It's also owned by a complete loon....