In my experience the only effective education about these particular drugs is experimentation. Problem here is that if they were administered safely and legally, there would be (predominantly) zero downsides. Barring unexpected negative side effects, the only time "this is bad" comes into play is long, long after addiction takes hold. You can tell somebody for 30+ years "this is bad don't do it" even up to the point of using unethical methods (i.e. force a teen to smoke a whole pack of cigs, or give a preteen a shot or three of Popov)... it doesn't really click that first time, or even after several times.
The missing element with drug legalization is the preventative aspect. It simply doesn't happen in large enough numbers using the exposure/education method.
However, shame based propaganda has been showing significantly positive(?) results with cigarettes. Most people I've e countered from younger generations cannot fathom smoking a cigarette. Vaping, sure, but stinky cigarette? Ewwww, gross.
Meth and heroin legalization and "it's all good if you're responsible" mentality isn't going to work.