I have self-hosted my own personal email server since the late 90s. It has been a tedious, often unpleasant chore. I hate email. But it's the one thing I've never compromised on, because to this day they try to tie your identity to your email and giving up control of that seems insane to me. Apps that use your phone number are doing the same thing, but you can't self-host that, so I won't use them. I'm sure Signal is very nice and people keep recommending it, but my phone is an untrusted device, and my phone number is an untrusted identity I don't control. I am not going to use it for anything important.