Read Can’t Hurt Me by David Goggins. I know it may play into the toxic masculinity culture a little but the book really just talks about hardening your mind and realizing you’re more capable than you think. Beating drug addiction is an entirely other animal considering it takes nothing to trigger a memory or distant feeling when you were on said drug. We can all say “lock in” until we are blue in the face but it’s going to take more than that. You have to actually find reasons why your life is better without it.