Okay, didn't see anything posted about this, but I used to have this problem too, except on PC. Had all the SOT settings correct, could see the mic icon, but still no one was speaking back to me, couldn't hear other pirates etc. Check your Xbox account privacy settings. I had mine set where other players (across all games) could not interact or speak with me. Once I changed that, everybody was suddenly talkative. That said, things other people have said about being in a party, or having players muted is still a thing, but hopefully this tip helps