I reckon it could work by not really letting the information trade hands, like letting the government be the middle man in this situation. You’d send like a confirmation to your government saying: “here’s my dns and my modem address, whitelist me for adult content”
First of all, your residential connection doesn't even have a stable address, we're still at least a decade away from full ipv6 adoption. Secondly, do you really want everything you post online to be easily trackable back to you?
Even if you for some reason fine with the government spying on everyone, surely you'd rather that database not exist at all, least malicious hackers get their hands on it
Everything that you post online already os easily tracked to you, and yeah, i’m fully on making ppl responsible for their actions