I feel like we're talking about completely different things. What's currently implemented in various EU countries is basically OAuth, where user attributes are verified by the state. Being able to map that account back to a specific person isn't a bug, but the whole reason for the system's existence.

Here's a marketing page for a WIP pan-EU project to implement this kind of digital ID: https://commission.europa.eu/topics/digital-economy-and-soci...

There are also various plans for age-verification schemes that should (partially) preserve anonymity, but those aren't implemented and it's not what people mean by "digital ID".

I work in Zero Knowledge Proofs, and they are a great mathematical tool. But they ain't magic.