iPhones are pretty easy to use with parental controls. Use Screentime parental controls to disable all browsers, App Store, set ratings for music. The parent will have to be on top of it, ie each time the kid needs an app for school you'll have to temporarily enable the App Store then again disable it. My wife agrees with me on the approach but is not vigilant when she uses parental controls (she often forgets to disable the App Store after adding apps). So I've had to do all the phone parenting x 5 kids. I'd really recommend a team approach because it takes time.