That is the only real solution. It removes the lobbyists with their bad verification schemes and untrustworthy software. You don't need untrusty flaggers or untrustworthy official authorities. In no way can nations be responsible enough to not attempt constant sniffing attempts. My nation couldn't keep itself from spying of corona app users.

This can also be broadly implemented, any other technical solution won't be widely spread anyway.

I don't think authorities care about child protection though. They could have legislated malicious advertising practices and a lot of similar bad influences, but didn't.