Same struggle here with 16 year old. I am including a link here to the instructions on how to set up restrictions. Some parents are blocking youtube completely. SETTING UP GUIDED ACCESS AND RESTRICTIONS
Here is also a link to our schools resource page. There are lot of other links here that are worth looking at too. MINNETONKA IPAD PARENT RESOURCE
For the phones in our home I have trialed three different programs and found Qustodio to be the best. You can have one account that you can put on all of your electronic devices (computers and phones) and it will add up all the time so you can set limits of how long they spend on ALL screens. You can even see what they are texting and it has a location tracking setting. The limitation is that we can’t put it on the school ipad but if you lock out youtube or games that should help.
We are the guinea pig parents learning how to parent in this age. I am sending you strength! We all need it 🙂