I don't think you'll find anyone in the fediverse willing to defend face-based age-verification systems. It's a complete farce to pretend it's ever going to be viable, even if you completely ignore all the obvious privacy issues and how easily-bypassed it is. People's faces just have far too weak a correlation with their age to get the kind of bright line result a law like this needs.

Uploading ID is a better option. Still bad because it kills all anonymity/pseudonimity and introduces enormous privacy risks. And is still not difficult to bypass. But if options for age verification were political parties, this would be the LNP, to facial-aging-AI's One Nation.