Signal usernames are not a solution. You still need a dang phone number to sign up. That's BS.
Discussion
There's lots of free temporary SMS websites. I know because I use them to sign up for Bitcoin exchanges that I'm not supposed to use.
The numbers get deleted, so as long as you can login on a new phone *without* that number, you're ok.
Yeah, that's true, and I've read about other ways to get signed up without having to give your "real" phone number.