In my opinion, Signal isn’t trying to be a Matrix alternative. Anonymity between users isn’t their objective, they mostly want to be a none profit alternative to WhatsApp, Messenger, etc… with strong E2E encryption. Phone numbers is ultimately the best way to discover new users as soon as you install the app.
For me it is Fedora as well. Before that I was using EndeavourOS but wanted to use something a bit more stable. Haven’t distrohoped since!