Okay, lab rats repeat a set of actions, go through a maze and habitually visit or laze around a place if they've been conditioned to expect some powerful reward, right?
Delicious food is the reward for the rat.
What about people who are behind screens more than what doctors are saying healthy? Are they being rewarded?
Yes, right? The anticipation from scrolling through timelines, boards, recc. feeds messages or images awaiting something new and exciting, the novelty of online videos, news and media, the desire to see what happens next in a show, story or movie you're binging, the eagerness that comes from waiting for someone to respond to your thread, post, comment, creative work etc., the way you're pulled into an engaging video game, the sexual excitement that comes from people replying to your lewd selfies or Tinder profile, the sexual release from porn, the conversations you have, the emotions felt during all of this, the food and drink you physically consume while you're on your computer, the time and effort invested...
All of this and more fire up the reward system, right?
Therefore, all of this would cause us to, like the rat, repeat a set of actions and habitually laze around our screens, yeah?

In that case, wouldn't limiting how often we do any of this/outright restricting some of it get us to a level of screen time more to attuned to what doctors consider healthy?

E.g. Eating all food at the kitchen table, noporn, fapping through imagination only, avoiding/limiting time with anything with a recommended feed, timeline, wall of messages or board style, treating games, shows, movies and fictional stories like a fat slice of cake when you have diabetes, talking to people in real life to establish romantic or platonic relationships etc.