If a kid wants to get in trouble they will do it. Smart phone or not.
Resentment rebellion is real and can be worse than anything a smart phone can do and happens with every change in generation. However times are changing much more frequently than even just 10 or 20 years ago.
Nothing is black and white (I.e. don’t kill, unless God says it is ok; ask Nephi, etc.)
Good luck is all I can say.