

That’s about right. The matrix protocol, while quite big on protecting messages, is not quite so worried about the metadata. This can be minimized if both users are from the same server.
Whether the metadata leakage is important depends largely on your threat environment.
As for Signal not having anything to be able to hand over… I’m not sure I take them at their word. That may just be me though, I’m a distrusting bastard.


Last I’d heard, even the NSA hasn’t been able to find an encryption that is quantum safe. And the some of the one they had found were broken using traditional computers. I strongly suspect that your messages will remain reasonably private for at least the next decade or two.