FaceTime? That's probably the closest to what you're looking for. It's end-to-end encrypted, runs on (Apple) phones and computers (which is its biggest weakness

FaceTime? That's probably the closest to what you're looking for. It's end-to-end encrypted, runs on (Apple) phones and computers (which is its biggest weakness for this use-case), does not require joining a "community", and is dead-easy to use. Signal is also great and doesn't require an iPhone, although you have to convince everyone to install the app. Everything in this space is a trade-off, unfortunately. To my knowledge, there's no open-source, end-to-end encrypted, decentralized, peer-to-peer, mobile-friendly, and easy-to-use audio/video calling platform. Assuming that the solution is end-to-end encrypted, I'm not too worried about it being OSS or P2P. For non-technical friends and family, the mobile-friendly part is far more important. Even mobile-only is probably fine for this particular purpose.