That’s a problem then with government. I mean just because they “waste it” in your eyes does that mean we shouldn’t tax anything?!
Legalising something doesn’t mean you eradicate criminality. There’s people who sell dodgy chickens, builders who mix poor cement... you get my point.
In terms of what you legalise I’d suggest it happens in stages but I’d look at legalising and controlling the most widely used first. I’d take medical opinion, law endorsement opinion and then draw up a plan. It obviously has to be widely researched and discussed and properly implemented. But if I was a dictator (oh I dream) then I’d probably do the following;
1) Legalise cannabis and introduce cafes and pharmacy style shops to sell it. I’d make it legal for anyone over 18 and I’d introduce a government drug ID system. A little like a driving licence. You need to apply, take a theory test (which gives you the medical info on its harms) and then once you’ve passed you are given an ID. I would limit THC allowance in marijuana and obviously products would clearly be labelled. Mild users could buy weed with little potency (like a beer) and more heavy users could buy stronger stuff (like vodka). However data would be kept on every individual and anyone who has clear signs of addiction would be dealt with (how are this stage I don’t know - needs further thought)
2) cocaine - you’d eventually have to legalise this as it’s so widely used. I wouldn’t have it sold in cafes or anywhere, only in the pharmacy style shops. Age limit would be 21 and over. Potency would be kept low and quantity checks in place. It would be much more regulated than cannabis.
I think you’d have to take every drug on a case by case basis but this is just an example to answer your question