I haven't tried it, but Signal supports not sharing your phone number/just communicating with usernames: https://signal.org/blog/phone-number-privacy-usernames/
You still need to use your phone number to sign up, though.
> You still need to use your phone number to sign up, though.
Which defeats the whole point. What if the FBI politely asks Signal about a phone number?
> You still need to use your phone number to sign up, though.
Which defeats the whole point. What if the FBI politely asks Signal about a phone number?