If you have 2 hours there is no better guide than Andrew Huberman: https://www.youtube.com/watch?v=QmOF0crdyRU
Spiking dopamine levels with pharmaceutical drugs can do this in animal studies, but watching a show on Netflix or eating a donut is not the same thing.
The simpler explanation is that people who spend all of their time passively consuming rewarding activities (junk food, TV shows, Twitter, Reddit, porn) are getting terrible nutrition, very little physical activity, and no real social exposure. They're also piping a constant stream of negative news and unhealthy debates into their eyes and ears.
Going outside and going for a run is also rewarding and can also be shown to elevate dopamine levels, but nobody is going to argue that it makes you "feel shitty and unmotivated".
You can't reduce everything down to one, singular chemical in the brain. Human psychology and motivations are complex and not a function of singular chemical "levels" in the brain. Reward is also a complex topic that involves multiple systems across the brain, especially opioidergic pathways that moderate much of the sensation of reward. Dopamine is also used for functions like movement (think Parkinson's) and even encoding negative stimuli that you dislike.
This pseudoscience idea that "dopamine equals motivation" or that you can modulate your entire motivation/reward circuitry by playing games to modulate dopamine is an egregious abuse of the science.
That's not the simpler explanation at all; that's actually a 2nd and 3rd order explanation backed up by nothing but conjecture. The reward center and the pleasure center are separate; this is why people can get addicted to video games they hate, or they can doomscroll all day not really enjoy it, yet be unable to stop. Activities designed to spike dopamine as high as possible and far beyond anything seen in our evolutionary history cannot be taken lightly. It's silly to think that a healthy, active person is immune to addiction. Porn, junk food, twitter are all just socially acceptable, mild addictions, and just like any behavioral addiction like gambling, they are all driven by dopamine. Will you next tell gamblers they're fine, they just need to eat better and hit the gym?
I suggest you listen to the Huberman episode. Of course, he never claims something as simplistic as "dopamine _equals_ motivation", but there's wealth of evidence that he cites in the episode that the two are intimately related. The second part of your sentence is actually pretty close to the truth rather than an egregious abuse of the science, though it depends on what you mean by "playing games to modulate dopamine". The entire episode is about the topic, and I strongly recommend it.
> You can't reduce everything down to one, singular chemical in the brain. Human psychology and motivations are complex and not a function of singular chemical "levels" in the brain.
I'm pretty sure you won't find any instance in the episode where Huberman claims to reduce everything down to dopamine.