IMHO, drugs of dependence are suicide, but with extra steps. And with a non-trivial chance of being saved, but with a lot more harm inflicted on third parties.
I never met anyone who tried heroin / fentanyl without going through suicidal thoughts first. I'm sure such people exist, but I've not met one.
If hard drugs were legal, people would still kill themselves with them, but there'd be less adulteration, and no need to commit crimes of addiction (pharmaceutical-grade heroin in a thing for terminal cancer patients, and less than $1 a hit. Fentanyl is even cheaper to manufacture.)
We're not saving anyone by keeping them illegal, anyone who wants to find will. But by keeping them illegal we greatly empower the prison-industrial complex, the secret police services, and police informers aka organised crime bosses.