I hope I’m not too late to the party. Recently I noticed guys behind PeerTube (fully decentralized network for storing and sharing videos - pretty much like youtube, but without any central nor federated authority) want to implement real-time video conferencing capabilities.
What about Delta using their app/SDK? It sounds to me simpler than integrating e.g. Jitsi SDK which is dependent on at least one non-email server and thus not the best fit for Delta’s decentralization goals (btw. I love Jitsi and use it from around the world for some years already, but I don’t think it’s the best fit for Delta).
Btw. another benefit of PeerTube could be to overcome the ~25MByte attachment size limit by simply using PeerTube as storage. This is though not a well though out idea, so take it with bigger grain of salt.