People can't message you if you don't want them to, and you can't even get unwanted requests because that would require the numbers at the end (e.g. DiscordUser#1234).

If you're so concerned about it from people who are already in the same server as you and thus already had that information, you can just disable server messages from people who aren't on your friends list. But again, that's information that by default was already out there, so it's not even anything from this comm.