While no system is perfect, technology has improved a lot since you were a kid.

For one, like it or not, many phones no longer allow custom ROMs or tampering. But even that aside, network inspection takes way less processing power now so a basic gateway can now handle dynamic block lists, DNS filtering, VPN detection, etc. If properly implemented it could ensure your parent’s use a password with good complexity and require MFA in order to turn it off.

Now, circumvention techniques have improved as well, but cheap cryptography really changes things and it can be used to make a very secure system. I think this is where our effort should be focused, on making sure ISP provided hardware has these options available to parents. It makes much more sense than trying to force this on all endpoints.