There are a lot of GOP-controller legislatures in the USA pushing through so-called “child protection” laws, but there’s a toll in the form of impacting people’s rights and data privacy. Most of these bills involve requiring adults to upload a copy of their photo ID.
There’s no way for a government to do it that wouldn’t interfere with adults’ privacy.
There technically is, but it’s going to be a while until the government is ok with it. It’s called zero knowledge cryptography, where a user could prove they have an identification that is government issued, and that they are of age, without revealing any other information.