What drug doesn’t have any potential side effects? The solution is criminalizing public disorder, ideally with a rehabilitative bent. Not wasting public time and money on criminalizing drugs and pursuing possession charges.
Aspirin has side effects.
In my opinion and experience your requirements could include the vast majority of legal pharmaceuticals.
Say goodbye to anesthesia, I guess.
No mode alcohol or tobacco then.
Plenty of drugs are good for you when used appropriately. I use psilocybin to great personal benefit. I’d recommend trying it if you get a chance.
Psilocybin is technically not a drug. Entheogens have no serious (bad) side effects, if they have them at all, if you use them sparingly and know how. And they are not for everyone. You can microdose shrooms but you cannot sell them on the streets. There is a reason why they were treated as a sacred plants. Comparing them with meth, dope and similar stuff is ridiculous. Or plain insidious.