Keybase is better than Signal. You may not like it's current owners but it still works, still functions, and can be used to chat privately. It's entirely OSS on the client side; and server-side software isn't provided; but with an open Client; it's likely trivial to reverse and re-implement your own. (Keybase itself doesn't provide their server code; it's private due to abuse constraints)

Keybase is End to End Encrypted. It may not be as "feature rich" but all features are private.

I'm not sure if it's indev anymore though; and it does allow you to be as public or as private as you'd like to be about your identity.