You don't really have to legalize everything everything. Just enough that path of least resistance takes most users to legal options.

There are some really shitty research chemicals that exists solely as substitutes for amphetamine, MDMA and LSD.

There isn't a huge reason to ever legalize Fentanyl and it's even deadlier cousins. Heroin will do just fine or if there are safer synthetic opiates that still do the trick they work just as well.

Most Psilocybin are extremely safe. You like need a few legal benzos.

Commonly used drugs from the last 20 years are there because they are all relatively safe. For the user and everyone around them. Most people aren't looking for psychosis, heart attack or respiratory failure.