Biden is in the Executive side of the government. He is in charge of executing the work of the government. In your example, he chose how those organizations executed their business. He did not choose what outcome those organizations had from the work he directed them to execute. It’s like a professor telling you to research a new thing. They can tell you what work to do and how to do it, but the results of your research should be out of their hands.
Biden can force them to study legalizing weed. Biden might even be able to propose a law to legalize weed that Congress can vote on, but he knows that vote won’t pass and that the Speaker of the House might not even allow it to come to a vote in the House.