"It's difficult to quit smoking."
Everybody believes this statement, even non-smokers. Nobody understands it. It's short, lacks clarity, and offers no insight into the problem. It doesn't even define the problem. It's really just a statement about unpleasant feeling.
Stop believing it. It's wrong view, coming from popular culture. Smoking is one thing, difficulty is another. If you glom them together you make the situation incomprehensible.
Smoking is an unskillful and harmful activity that you want to stop. Okay, no problem there. Difficulty, what does that mean? It points to the stress and suffering that you create inside, when you try not to smoke.
If you could remove the difficulty (the stress and suffering) there would be no problem, would there? So what's the actual problem?
See what I mean? People don't even know what the problem is. Because they don't understand stress and the cause of stress, they look elsewhere for a solution. This is the lack of skill (Avijjā) of the average person.
Fortunately, the Buddha understood the problem you're facing. He understood suffering, the origination of it, and the cessation of it. It's all he taught.
You need to learn to see where your unskillful thoughts are causing you stress and suffering, and then abandon those unskillful thoughts in favor of more skillful ones. This is true in quitting, and also in any other human activity.
A few suttas that will help you to better understand your "problem":
I will admit that the above teachings may be challenging for a newcomer, but if you like a challenge, you'll find them worth the effort they take to penetrate.
"Is there a way to build willpower and discipline from scratch?"
As far as willpower goes: If you mean making a good determination, resolving on it, and persisting in your efforts to achieve your worthwhile goal, I'm all for that!
"Or is the only escape to find something else to do?"
No. The escape is through comprehending your problem to the point where you see it all clearly. When that happens, you will see its allure and drawbacks, you will see exactly when and where your stress arises and ceases, and become disenchanted and dispassionate about the whole (internal) process—that's the escape—that's the easy quit.
Venerable Thanissaro says there are three levels of learning: First you listen, then you contemplate what you've heard until you think you've got it, then you try it. "The things we know best are the things we do."
Take your time, you can't rush understanding, but when you're ready, you'll know.