Nostr has no single server like Twitter (or Facebook, Parler, Gab or other centralized social networks). Neither does Mastodon. So if my understanding is correct, you will only see posts from people using the same relays that you are connected to.
(I'm not a techie, so I'd be happy to stand corrected.)
Ah. That's not my understanding as relays talk to each other. So a message on one relay is broadcasted and others pick up on the message
Again I'm not a dev either but that's my understanding.
There are like over a thousand relays right now, but on the global feed you will only see posts from the relays you are connected to. So there is a lot more action going on out there then you can actually see.
