I attended a talk in 2019 by Sir Tim Berners-Lee on Solid, which sort of seems related to what you are getting at. The idea being that you own your data/identity, and can decide to share it with third parties. It goes over things like files, but I believe login identities were also meant to be part of it, I see when I scroll down:

authenticated by a decentralized extension of OpenID Connect

I’ve been wondering recently, especially with Pixelfed adding login with Mastodon recently, if anyone has heard or experienced anything with that project. But considering I haven’t seen it spoken about or implemented since then, I’m not sure I should be hopeful