We build Signal in the open, with publicly available source code for our applications and servers. To keep Signal a free global communication service without spam, we must depart from our totally-open posture and develop one piece of the server in private: a system for detecting and disrupting spam campaigns. Unlike encryption protocols, which are designed to be provably secure even if everyone knows how they work, spam detection is an ongoing chore for which there is no concrete resolution and for which transparency is a major disadvantage.
If you are using Signal for anonymity, then you need to learn how to pick the correct tools for the correct job. You go to XMPP or Matrix or Retroshare or some chat over I2P for that, not Signal.
The only thing you can achieve properly, for the most part, is pseudonymity, and not anonymity over Signal, because your SIM is being tracked, unless you have a working VoIP provider that cannot be traced back to you.
I agree, but that doesn’t mean everyone is on the same boat. Matrix/XMPP clients still don’t have as good UX as Signal.
You can choose beautiful UX or you can choose a workable UX plus features you need. Element UI looks fine to me, as does blabber.im.