@lumi i would argue that matrix and xmpp have less privacy than signal?? you're relying on your instance admin being a good host and not prying on your unencrypted room messages, or taking the burden upon yourself and hosting your own instance on your own, very much identifiable domain.
at least with signal, i don't believe they even store your profile data on the server, besides temporary caching for device sync.
also i've discussed the matrix ecosystem with a bunch of folks and the collective opinion seems to be "they make too much money to ever separate from element or do much of anything to improve the ecosystem"