zap stream is currently the most widely used nostr streaming service provider whether you self host, use zap stream, or use another provider - primal apps will pick them up

Ok, cool. Thanks for clarifying

One more question. So even if it's not on zap stream, we should still be able to zap the stream from the primal feed?

Zap Stream is the most widely service used because it's the only one that exists. Self hosting requires you to program and mess around with the server which is something the average streamer can't do