The concept is fine, but even the best known implementation is impossible without putting an unacceptable level of trust in one group.

This should be parental controls - make websites declare a rating, then let the owners lock down devices

Nothing is going to be absolute, but we have to prioritize freedom or soon our Internet will look like China's. They've already been talking about banning vpns and kosa would make you tie ID to anywhere you can post - all social media is considered possible adult content by default