BlazingBonfire

No.
Briar doesn’t need a phone number or email when you sign up. I only know one person who uses it and he highly recommends it — I have my bluetooth off so I don’t use it. But check it out:

https://briarproject.org/how-it-works/

I’ve been using Delta Chat, Simple X and Matrix (on FluffyChat) and haven’t had any issues with any of them.

Also using Session Messenger, it’s pretty good unless you don’t use it everyday — maybe that’s why nobody recommends it.