Matrix's existing E2EE has identity verification as effectively one- or two-hop web-of-trust using QR codes or emoji comparisons. It's not impractical for users, because everyone's familiar these days with scanning a QR code as a mechanism for logging into an app (c.f. Discord, WhatsApp, Signal etc). So as long as you scan the people whose identity you care about, you're sorted, and it's much easier for normal users than the clunky old PGP signing parties of years gone by (plus it doesn't leak as much metadata, given it's just one or two hops of trust).