Stop buying it. Starve yourself of it by just not having it around.
Keep a tall glass or bottle of warm water with you when you’re junking on content. Keep sipping it. Slowly. Over time you’ll finish the bottle and get up to pee. That’s there number 3 comes in.
Recognize another harmful pattern here. Is your approach to watching content affecting your mood or causing you to spiral into junk food addiction? Maybe cut down on the YouTube videos. Or if you enjoy them a lot, combine them with some other activity you can do with your hands - drawing, writing, lifting weights, anything. Basically understand that your hands are idle while your brain is engaged and that’s causing you to reach for that packet of food.
Recognize that junk food is an addiction. Deal with it as you would an alcohol or nicotine addiction. You can go cold turkey or taper down. But you have to commit. You have to hold yourself accountable. But do not let yourself get bogged down by failure. Addiction is difficult to deal with. Deal with it anyway.
I find your third point interesting. I read something a while back that suggested some cigarette smokers got started or hooked because of a compulsive need to have hands and/or mouth preoccupied, particularly in stressful situations. I think it was called something like digital-oral fixation? Anyways, I wonder if that's one of the reasons behind constant snacking. Maybe a stress response paired with a compulsive disorder...
It’s actually incredibly common. Think about all the people who bite on the end of their pen or always have a drink (like a water bottle or coffee) to hand