I’m a parent of three children (two of them school aged). I’m also a School Psychologist and I have ADHD myself. My advice is this,
1. Don’t give up. Your concerns are valid and real.
2. Assuming your kids already have a 504 or an IEP, you should call and request a meeting. If you dont have a 504 or IEP you need to start there.
3.At the meeting ask your team if there is a way for your kids to do their homework at school. Many schools offer homework clubs, supported study halls, and by High School, most teachers offer office hours. The point is, the kids get their homework done at school and most nights they wont need to bring their ipads home at all. If they are on the ipad, at least you know it isnt about school anymore and you can go back to setting realistic limits for screen time at home.