In regards to the drugs rappers take influencing music quality I’m gonna have to disagree with there not necessarily being anything important to say about being blacked out on Xanax. Maybe not the high itself but abusing Xanax/lean/whatever is likely a sign of some sort of underlying mental health issues. YBN Cordae for example openly raps about his past xan addiction. The turbulent emotions being suppressed by the drugs can provide a wealth of artistic material.
That’s not to say I don’t love me some psychedelic rap especially while tripping but I don’t necessarily think that a rapper using one drug over another will provide them with superior artistic material