I am so sorry for what you are going through, it is so tough to raise children without ADHD! The technology is a detriment to our society at large. I’ve experienced a little of what you are saying about addiction, ours was with the Wii. Years ago I decided to pitch it seeing how my boys just wanted more and more. No regrets! Unfortunately, the schools have stuck these addicting devices in our children’s hands. We chose to Homeschool so we have complete control over the technology. My children do not have computers , iPhones , or iPads. We just don’t allow it. Once our children hit college age , they took some online classes and had no problem navigating through. They don’t need this stuff as children. It consumes them . If homeschooling is not an option, possibly you can find a school that supports you better. Interestingly, many of the techie people who work for these companies use Montessori type schools ( no technology!)They know it’s addictive!
In the end , we are the parents and we should be in charge . Our kids need to respect any limits we put on the electronics , if they don’t then out they go ( or no borrowing moms car , not going to the mall or movies , etc… some kind of punishment for disobedience). Thankfully, my son with ADHD and on autism spectrum has a doctor who is supportive and agrees that the screen is not good for kids with these challenges. Good luck to you and don’t give up !