Decriminalization is never the correct approach. It leaves the trade in the hands of ruthless criminal gangs who are the source of much (most?) violent crime, whose product is not subject to quality control, and who for reasons unknown to me, feel that lacing their drugs with cheaper fentanyl, thereby killing a lot of their customers, is a good business strategy. You basically get all the downsides of drugs being illegal and all the downsides of drugs being legal at the same time.
Full on legalization (which has to be at the Federal level) could make sense if the trade was shifted from criminal gangs to legal pharmaceutical manufacturers, with attendant quality controls, and money now spent on drug enforcement shifted to fund treatment programs for whose who realize their addictive habits may no longer kill them, but ruin their lives (and the lives of those around them) anyway.