You do not need to control the entire internet. Put time limits on connected devices. Use parental controls. Talk to your kids about what they do online. Set clear boundaries. Reward good behaviour. Talk to other parents to align these limits to avoid social issues among the kids.

We may be agreeing, I'm saying there is no battle tested, privacy safe technical method of verifying age online, and this the controls need to be in the physical environment and setting social standards for social media and phone use.