@cwebber I read to the end and e2ee is not touched again (totally OK, the subject massively hard in a decentralized context, and the thread is, hum, not short already).
I suppose you're aware of that, but just in case, and for other readers : @soatok gave himself the challenge to deliver that, up to the federated key management protocol spec : https://soatok.blog/2024/10/12/ambition-the-fediverse-and-technology-freedom/
(Independently from w3c and, it seems, with strong view about how it should be done)