I ain’t read shyt (like areal coli poster) but just what level of verification are they looking for? Wouldn’t this be like alcohol sites where you just click you’re over 21 or enter some bullshyt birthday?
The measures you're describing are already in place and are also insufficient.
You'd visit pornhub, authenticate with some service that would send a token to pornhub verifying that you're of age and that's it.