This is probably a bit left of field as a tip that I personally found helpful (note that I do vape, but with almost no nicotine simply for the hand to mouth habit which I can’t break):

So I always carry a box of cigarettes with me wherever I go, having them on me means that I never have that “oh no, I’m out of ciggies. Need buy cigarettes immediately at any cost” feeling and it reminds me not to smoke.

Also know that having a single cigarette isn’t game over. You got this!