I'm using Matrix/element. I rather not give my phone number, you see, which is must-have for Signal. I have installed the app in my family's phones, and they were accepting, so all is well. I don't need to communicate through private messaging with anybody else, so who cares if others don't use matrix?
I'm not interested in running servers, in fact, my ISP doesn't allow it anyway. I need something private that doesn't ask for too much info off of me, and that's why my solution was matrix, and not signal.
You can. But you're not going to. Signal isn't federated. Not only do you need to self host your own server, you need to build your own clients, and then have everybody you want to talk to using your specific clients talking to your specific server.