You're going off-topic from the OP question :-) But to answer your new question : I do not trust Matrix enough when it comes to privacy. I know that this link is old but still. https://disroot.org/en/blog/matrix-closure
Then again I do not trust Signal that much either but sometimes compromises need to be made to get things done. With XMPP the end user can host their own server if they wish to, without meta data going to a centralized point. And video calls via XMPP and Conversations were a pleasure to use when I used it during the Covid-19 pandemic.