Coincidentally, I was recently diagnosed with ADHD after a lifetime of that going untreated, and I think it's given me a lot of context into experiences I've had.
So, the video is correct that dopamine is part of the brain's reward system and that your brain kind of craves and will seek out dopamine, but "reward" in this case is a slightly more nebulous term than is being implied. Dopamine is released whenever your nervous system is aroused or stimulated. When you hurt yourself, or have a panic attack, or have an intrusive thought, it's a miserable experience for you, but you're still getting dopamine from it. Your brain doesn't actually care if you're doing something enjoyable, taking a stupid risk or making yourself incredibly unhappy. That's a big part of why living with untreated ADHD has been so debilitating for me, it's not just that I'll sit down to do some work and end up procrastinating on twitter, it's that if I force myself not to procrastinate, my brain will still find ways to get the stimulation it needs and often those ways are outright harmful.
And that's the second thing, when I say need I mean need. If your brain isn't getting enough stimulation, it will find ways to get it. Trying to "dopamine fast" is at best going to do nothing, and at worst is going to make you more distracted. What you actually need to do is to make sure your brain is getting enough stimulation to begin with. Add positive and pleasurable rewards to whatever it is that you're struggling to do. Use a productivity tool and build rewards into completing objectives. If you find you're spending a lot of time compulsively browsing social media, build times when you can do that into your schedule as rewards.
I think the thing that's probably happened over lockdown is not that people have become overstimulated (actually being overstimulated is an extremely unpleasant and uncomfortable experience) but that people have maybe not kept up the organizational and motivational strategies they used to rely on. A lot of people probably also aren't exercising as much. Both of these things are really easy to fix, and you don't need to try and "reprogram your brain" (which you cannot do, your brain is the one you're stuck with sadly).
