My fella found this talk useful. https://m.youtube.com/watch?v=gnSEbLX94Tk
He used to smoke the mild stuff (low THC), but it's the cigarettes he's been struggling with. He's on his third attempt, but after using the technique (TL;DW: your brain doesn't understand negative commands, replace it with a positive command. Instead of "I need a joint", try "I need air" or "I need clarity" or whatever feeling you're aiming for) he's feeling a lot more positive that he'll stick with it this time.
I tried to get him to read the Allen Carr stuff, but he's not much of a reader. Other people swear by it though. It's available on a certain library beginning with z if you want to give it a taster.
Also learning a new skill can give you the same dopamine hit that your addiction does, so take up a hobby, learn a language, etc.