AA is a good thing for many people.
I am not sure it would have worked for me, because as a drug user, I would have gone to NA, and knowing myself at the time I probably would have just looked for new connections in the group from which to score more drugs.
My battle had to be fought alone, but that may not be the case for all.
But yes, the 12 Steps are legit, and the entire conflict begins and ends within one’s spirit.
I am not sure how one who does not believe in the spirit tackles the problem of addiction. I just don’t know.
There is a chapter to the Agnostic in the big book *the AA book*.
I know a devout atheist who is in AA. His higher power is nature (God as you understand him), so it does work for him.
Apparently there are NA’s in the local AA, since there are no NA groups in the immediate area. They are welcomed in to the group even though focus is on alcohol. And alcohol is considered a gateway in some circles.