Family Sharing App Blocking and Time Limits not Applying to YouTube

I am frustrated that despite using Family Sharing with time limits and app limits in place, I cannot seem to block YouTube on my son's phone. He's 15 but still needs management of his screen time. I've blocked the app and YouTube itself but he can still use the app at any time. He's a smart kid and has found a way around this; aren't Apple Engineers smarter than my 15 year old? He's on an iPhone SE with iOS version 17.4.1, and I'm on the same (as Family Manager).