@leanderlindahl
In Austria we have #IDAustria it's a kind of #eID it should be possible, to configure this as #IdP to #keycloak and keycloac is configureable in many fediverse-services.
I think, i will register as serviceprovider for idaustria to try this for my services. But the process to get this work is between a few weeks and one year.
The you have such a thing you want. Including age-verification. For "tante erna" is it too complicated. For techies as i am, it's too centralized.
But did you read, what i've written?
There are some serviceproviders out there, which serve a bunch of fediverse-services with such a single-sign-on solution.
Thrn you login to tchncs.de or adminforge and can use all the funny services there with one login.
But try to understand, what it really is, what you want. It's just another solution of centralized surveillance, if you want to do ALL your daily business with just one account. It's that, why i left facebook, google &co as much as possible. Because i don't like this possibiluty of surveillance