Should mention that Slrpnk.net hosts an XMPP instance which any Slrpnk member can access using their existing slrpnk lemmy login. You can access it via our Movim instance in the browser, or from any other XMPP client :D

I believe you should be able to create a room there that other people could connect to.

It's different from Discord in that you can't have a whole server with various different categories and rooms, it just has individual group chats (though possible to create multiple group chats of different subjects).

If having a single big server with different rooms is needed, I think Element (Matrix protocol) can do that.