> Which part of that is avoiding the distopian control?

Your ID is already controlled by your government, and we don't call that dystopian control. With privacy-preserving age verification online, the government doesn't learn what you do with the cryptographic token that proves that you are old enough, and the website doesn't learn who you are. So it's exactly the same situation as today, except that now there is age verification.

> how does this work on an open source operating system?

First, it can be open source and have DRM and attestation. Android is open source, for instance.

This said, I hate the idea of remote attestation. And for age verification, I strongly believe that it is not needed. We don't need to make it work everywhere all the time, it just needs to help. I can imagine a privacy-preserving age verification system that helps with some problems (e.g. make social media or porn less accessible to kids) without bringing dystopian control and without making it super hard for adults to access social media and porn.

But I absolutely hate the idea of remote attestation.