In signal, You can turn off phone number visibility and make it so that you are only searchable by username or qr code. Yes, it’s centralized, but signal is a nonprofit project with generally good guiding ideals. I use matrix for some things and signal for everything else.
“The lawsuit isn’t the only place where executives have offered a pessimistic assessment of X’s business. The company’s owner Elon Musk reportedly told employees in January that “user growth is stagnant, revenue is unimpressive, and we’re barely breaking even.””