Tbf I’m unaware of a messaging service be it chat or email or whatever that leaks no metadata, afaik they all kind of have to by nature of needing to know at least where the message is supposed to go, if not where it came from, too.

Like, if Bob messages Lisa, the service has to at least know to deliver the message to lisa, even if it didn’t also that it’s from Bob.

If you know of one I’m curious though!