I have nothing against Signal. I just don’t have access to a phone number right now. I fully intend to use the Signal when I get a number. I know there is no silver bullet, no absolutes in the privacy world but I’m looking for any messengers that are generally considered to be private and secure on Android that I can try to convince my friends and family to use. I have a mid - low threat model, it’s just the thought of giving the Zuck anymore of my family’s data makes my skin crawl.
Aside from signal I would say your options are Simplex or Briar.
briar is pretty decent. no voice/video, but solid and quite private with multiple ways of getting messages out in hostile network environments.
edit to say: its also completely p2p using Tor rendezvous points with no centralization at all.