The privacy-preserving promise of this “double blind” method has inspired various countries to further explore and develop ZKP-based age verification solutions. In the European Union (EU), a ZKP age verification protocol is being developed as part of a European-wide EU Digital Identity (EUID) framework. However, some organizations have pushed back against linking age verification tools to digital identity solutions, citing concerns over potential misuse and user privacy. While the EUID solution is set to be released by the end of 2026, the EU launched an interim age verification app in the meantime.
https://www.newamerica.org/oti/briefs/exploring-privacy-preserving-age-verification/
So no country in the world has such a system that actually protects privacy in practice