TBH my kids have limited access to their (Android) phones using family link but I don't see option there to:

- block certain list of sites

- block walls inside YouTube for example

- limit amount of scrolling time Vs amount of learning time (this can be done quite easily)

So just give the tools to parents and stop requiring IDs for adults. What happens if kid gets adult's phone? And what happens when kid gets dad's rifle or car keys? It doesn't mean that all the rifles and car keys should now start to include blood sample based age verification mechanisms

--Edit--

Apple family management is even worse. The best I heard of is implemented in the switch console