We might be over complicating things here.

The governments’ focus might be on protecting genuine users (adults or not), not fighting fraudsters.

In other words if ZKP works for the vast majority of technically illiterate people with their EU ewallet, the job is done.

Absolutely. We don't look at the use of false identity documents as a failure of age gating tobacco and alcohol, it's just an accepted consequence that we try to mitigate knowing that we cannot stop all instances.