You might try a Matrix group instead. Doesn’t require a phone number and supports more than 1000 users unlike Signal. Search is bad though unfortunately.

tbh, I don’t like where this new product seems to be taking Beeper. I was a giant fan of Beeper because they were a huge contributor to the matrix project. But with them creating an entirely new app that doesn’t rely on matrix at all, it looks like they may be looking to pivot away and create their own client-side implementations rather than use matrix bridges. It would be sad to lose a contributor to the matrix space.