Privacy minded instant messaging quest.

Hi,

I'm looking for an instant messaging ( IM ) apps software/protocol that run on Android and computer

and meet the following requirements :

• Open source !
• E2EE
• Messages are send in direct ! (not passing by a server)
• handle group
• Truly private ! ( That's the tricky part )

The closest that I've found is Briar

• +can work without internet ! (bluetooth, local wifi, files !)
• + use TOR
• - Mutual party have to exchange key (or your can introduce someone)
• - sending media suck for now, poor image quality
• - no call or voice messaging

I've been looking for alternatives:

• Session
  • Sadly it keep ALL the conversation into server !!! so it's a no go.
• speek
  • I didn't try it yet, any feedback ?
• simplex
  • it look very promising ! (didn't tried it yet)
  • + seem to handle multiple profile in one !
  • + do not require that both party send an invitation !
    • and have also a optional long term address
  • ! I didn't found (yet) if the messages are send in direct or pass by a server..
    It's not P2P all the messages pass by servers.. too bad.

All post about alternatives or experience with the one that I cited are welcome.