Self hosting a password manager is great, but be sure to read up on keeping it secure, and don’t store anything important in it until you have working, tested backup solution. And re-test it frequently in a non-destructive way.
If you lose your password storage to a disk failure or something, you’re gonna be hurting for a while.
They don’t use Signal though. They use a clone called TeleMessage Signal which logs and archives all their messages on an Israeli server, and which a hacker was able to access before the service was suspended.
You can’t really help if someone forks and misuses software.