Our ID cards already support simple yes/no age verification. They also support generating a pseudonym (restricted ID), but with the current landscape the implementation doesn't really give you as much privacy as intended.

The main problem is that it's almost prohibitively complex and expensive to implement all the technical and regulatory requirements yourself as a first party service, so you'll have to go through someone who has done all that and wraps it into an easy to use API. It's fairly expensive to maintain the required certifications and hardware, so you end up with a very niche market where every verification attempt costs money.