Is SimpleX Chat the future of messaging? (youtube.com)
All messages are uniform, no device identifiers, no usernames. Has onion routing. You can run the server yourself. Funded by its users. AppImage for desktop, Android app. Servers are called 'routers' and are a chain for the packets. Traffic pattern analysis harder than with other communications apps.
Their login has a message that you, the user, commit to only legal content in public groups. In private groups who knows, but in public groups you respect the other users and their privacy.
Use of the app requires a second app, basically. Because to add someone privately you have to send them a QR or hyperlink they can click in their own Simplex app to link your two accounts. So he uses XMPP.
It does voice messages, voice calls. It also does voice to text.