I feel your defeat. I go through similar issues and I clock out after supper at least 3 times a week. What I can tell you is my child was put on a mood stabilizer (did not accept controlled substances) and this has helped GREATLY! Unfortunately, she still has the emotional breakdowns every so often BUT I am able to talk her through it and get her to “stop, think and reason” until the calm down time comes. In my experience, too much electronic screen exposure jacks her up due to the overstimulation to the brain. I award her tablet time from homework, positive behaviors (especially) and chores (which is SO exhausting and frustrating). I have had to remove “videos” from tablet time and only brain building games. I also have had to supervise electronic time so nothing inappropriate is not watched. Remember they will model what they see.
I myself cannot afford extracurricular activities. Do not give up! Unfortunately, sometimes tough love is necessary and removal of the tablet or calm down spot has to come in to play. These techniques do work and consistency is the key! Remember you are disciplining the behaviors and not the lovely child you have been given.