he sort of didn't. Biden started this in 2022, but the DEA and GOP congressional leadership log jammed hearings that were supposed to happen years ago. Someone just reminded Trump (probably be cause he needed a distraction), and he's clearing the logjam.

it's also mostly symbolic. moving medical cannabis products from Sched I to Sched III makes discussing cannabis policy on the federal level easier and makes some state regulation more straightforward, but nothing is more legal now than it was before. and all of this could be held up in court for months or years anyway...

the only meaningful path forward is full legalization

The only fun thing about Trump is that he will literally do whatever the last person he spoke to told him to do. He was probably hanging with Joe Rogan after he signed that order to research psychadelics and Joe told him it'd be cool if he worked toward legalizing marijuana too.