You should read:
Tip #5: Send private text messages with Wire
Tip #5: Send private text messages with Signal
Signal REQUIRES a Google account to work, that is so not in the spirit of open source. They refused people who created LibreSignal to use their services.
Wire (https://wire.com/) uses full encryption by default for everything: for chat, voice and video calls, group chat and file transfer. Creating a new account you just need an email address, you are not forced to use a phone number, that’s great!