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.
Addiction potential comes from the interaction between specific person and specific drug. I can pick up and put down opiates, but I stay far the fuck away from amphetamines lol.
To each their own, but opiates/amphetamines/benzodiazepines are the three that come to mind from pharmaceutical sources. Caffeine, nicotine& alcohol reign supreme due to legality/accessibility though probably