I looked at Matrix (which is what riot.im/element is based on) but have thus far not seen its advantage over XMPP+OMEMO. When you install Jitsi Meet you already have an XMPP server (Prosody, used for signalling and interprocess communication) so it is trivial to add a configuration for 'regular' use. XMPP is more open than Matrix and there are far more clients (albeit not all of them useable with OMEMO, alas). On an earlier installation I used eJabberd since Prosody had some problems with OMEMO back then but this is no longer the case.

I wanted to refute your points, but actually looking into it, it seems that xmpp is actually superior in many ways.