Learn to say "No".
Saying "No" to your Kids in certain moments is part of an Healthy Education.
Many Parents, Fear the consequences and the responsibility that comes after a "No". But it's your Job as a parent.
No Need to take it away completely in one go... like any "Addiction" treat it as one... Little by little... decrease the time spent on it...Day after Day, by Imposing a schedule... Like per exemple 1H today...then 30 min 2 weeks later and so on... But no need to cut it off for ever... or forbid it... it will backfire... better him/her doing it infront of you than behind your back...at least you have control upon it.
And in the Meantime, give him an "Occupation" whatever it's sport, Homework, helping at home, playing outside etc...
And LAst..; the most Important thing... Communication... Your kid "Understand" everything... a Child is like a sponge... As long as you explain your "decision" over and over... he/she will understand... doesn't mean he/she will accept it..; but at least the Aggression/Anxiety that comes with "taking it away" will be way lesser than "normal"...
Ps: Everytime you decide for whatever reason to take something away or restrain something...Always, make sure to tell him beforehand.