The problem Persona solves is: how can I log in to various sites securely without having to generate site-specific and inconsistent widely-varying sign-ins and

The problem Persona solves is: how can I log in to various sites securely without having to generate site-specific and inconsistent widely-varying sign-ins and security AND without having all my activities tracked by Google or Facebook or others etc. In short: how can we get "sign-in-with-Google" but with anything and not just these big players and protect privacy fully?