ZKP is definitely a good idea, definitely more open for this kind of age verification than anything else. And I don't buy the argument of "closing internet", social networks are a proprietary service and if you don't want to obey with the regulations, create your own website and post things there if you want. However you have to provide your identity to the domain name registry or to the intermediary. Also other serv…
Our ancestors here in France literally fought the nazis so you don't have to have a nazi-approved « Ausweis » to go wherever suits you. We would be well inspired to follow their example.