i threw out a few ideas in other posts and comments; heres another one though i just had:

for the people who want to do hard drugs, of which there arent many, its similar to gun use actually:

there arent many people who want to own guns (in the grand scheme of things), and guns can be considered dangerous to the user and others if handled improperly or improprietously

so, we make people get a license

where, they have to go to a school/class briefly and get instructed on gun safety and pass a test, and then theyre registered, and subject to laws

ok we could do hard drug use the same way-

its illegal unless you apply for a special license.

to get it, you have to go to a class on drug use, drug safety, accidental overdose procedure, understanding of cartel violence, anything like that, pass a written test, get a license/registration

then, its only available from your pharmacy with your special license, in regulated/controlled amounts, enough for recreational use, maybe factoring in things like your body weight, tolerance,

maybe also you have to get checked by a psychologist once up front, or once a year or something

maybe have to submit to laws similar to gun laws about travelling (if taking a gun in a car, you have to have it: in the trunk, with a trigger lock, unloaded, ammo in a separate container, also in the trunk); for drugs: cant drive while high; must travel to the pharmacy on foot, by public transportation or cab, must consume on premises then exit premises (maybe, to make sure no one's selling it, or, part of the license could be that youre trusted to take it with you and consume it on your own and not sell it, or not drive while high, but, will lose the license if caught reselling or driving high)