Great question Mahfuz
What I find often is that parents are rewarding children for following rules, rather than setting up a system where the child has a consequence of losing whatever their personal currency is when they don't follow through with expectations. I suggest parents make a list, that is clear for the child to follow, that contains both personal responsibilities as well as chores that are required. This list can be discussed and created with the child. But some of the items are non-negotiable. For example, a child will be expected to go to bed and wake up at consistent times, do their daily grooming, get dressed, make their bed, have healthy meals, attend school or work, complete homework, fulfill any meetings/appointment they may have, help with meal prep or cleanup, tidy their bedroom, eat meals with the family (without digital devices) and remain at the table for discussions for 20-30 minutes, engage in some family time with a board or card game a couple nights a week, get 15-30 minutes of daily outdoor exercise. And if any of these are not done, then consequences are put in place. So, if we're using a harm reduction strategy, a specific amount of time would be granted on certain days of the week/weekend - if anything isn't followed on the list, then the child loses that gaming time. That way, the child is making the choice to not play video games when they choose not to follow the rules/structure that have been laid out. I have found this is more effective than the rewards system. I suggest to parents that they can reward with positive feedback but not with tangible items.
I hope this is helpful.