I second Matrix, though I've been waiting for e2ee direct p2p (the Dendrite project) do be worked on for a while. Having something like that, that's truly decentralized while secure and hiding metadata where possible, would be a dream.
Yeah I've been following that. It seemed at the time the project didn't implement nearly all the specs as dendrite which was still lagging synapse.
Might take another look though. I really did want to use it since it was written in rust. Seemed it should probably be more performant, everything else being equal.