It's just Codeine man. Can't you buy that over the counter in the Netherlands? What you're chasing is an idea. Any Opioid will do. Pretty much any antihistamine will do. Don't waste the hours and dollars of your life chasing an idea propagated by others. I'm not trying to condescend to you, but you are essentially being made an utter fool by the media and the drug dealers and anyone with basic knowledge of drugs would know these things.
Research can make a pretty big difference in your life. If you had talked to me first, you never would have given your money to that dude, who was likely making fun of you with his crew before meeting you and again upon finishing his shift when he tells his crew runner that he made an extra several hundred dollars for the gang and he didn't even have to sell any of his Heroin to do it. Knowledge is power and knowledge is strength man, especially for us users.
We have been discussing the whole "Lean" phenomenon for what feels like a lifetime here on the forums. We discussed it and put it to bed back in 2013, so I'm admittedly surprised to still see someone after this stuff in 2022.