@andycarolan @neil I've been testing parental controls for at least 15 years, and I've yet to encounter a system that is sufficiently nuanced to give teenagers in particular access to things they should have access to while still blocking actual pr0n, mostly due to scope creep that tends in specific ideological directions (such as homophobia built into service).
More worrying still, pretty much all of them have massive scope for abuse by parents/guardians and include features such as tracking, usually implemented in ways that violate the rights of the child.
I don't have any great answers at scale to this - as an individual parent, I have a solution, but its success depends on my being extremely hands-on and technically/culturally knowledgeable about the internet, and it still reflects my biases about appropriate content.