IMO nothing touches opiates as far as addiction potential goes. That shit becomes as important as food, water, and sex to an opiate hijacked brain.
Still, yes I think they should be completely legal. Legalizing these drugs would completely destroy the black market for these drugs and greatly mitigate deaths from shit like fentanyl and carfentanyl.
Water 100%. If you don't drink it for too long, the withdrawal can kill you - but first it will drive you to desperation to feed your addiction. I think we should keep it legal but highly regulated, perhaps by appointing one guy to dole it out at regular intervals.
Ban dihydrogen monoxide
The Waterboy is actually a dystopian tale.