Okay I'll try and make suggestions on how to get dc to self regulate. Because I too am out the other side, but don't want come across as stealth boasting. DS has ADHD and has an obsessive addictive personality.
So these are things we did.
DC had access to screens and an old games console from mid primary school age. It was restricted times and had lots of other activities going on, when not on them.
by year 6, the restrictions were less but still had them. We talked extensively about game and screen addiction. To DS1 we spoke about how he does have an addictive personality, So it was very important that he learnt to recognise his own changes in its behaviour.
Any change in behaviour like, aggressive shouting and banging, not wanting to come off, would result in losing screens that day. (was always absolute Hell to enforce)
year 7 they got phones but had strict rules on them, plus they knew they had to hand them over at any moment for us to go through, we had to know all passwords.
(I still believe phones are the biggest concern for DC growing up)
gradually up until 16 they were given more time on games, but if they seemed to become obssesed with them, or their behaviour changed or their homework slipped, ect they were told to sort out the behaviour or they'd lose it all for a whole week.
We had to enforce this a few times, We told them it was to detox, and it was really really unpleasant for the first 3 days, they could be angry, whiney, agitated, and nagging. but we stood fast and just pointed out this behaviour was exactly the addition behaviour we were trying to avoid.
After day 3 things would settled down, and they would find other things to do and interact with us more too.(they actually felt the difference in themselves and addmitted they felt calmer) When they got screens back it was on a trial period of a week, any tiny thing like not coming off when asked would lose all their screens again for that day.
by 16 we left them to self regulate, if they played games into the night on a school night they was up to them, but they knew if they didn't get themselves up on time and into school, their behaviour slipped, there school work wasn't done, then we would impose detox again! but it didn't really happen after 16, because they had learnt to self regulate, they'd learnt they needed to go outside, to have breaks, to go to and do other things. We only had to point out they seemed to be slipping...
sorry it was a long one, but pp had been asking how to get them to self regulate.