If someone offered me $20 million (or whatever $$$), and said I could either A: sit over here and answer questions, or B: I get $20 mil and sit over here and answer questions, and do medicals, and run some sprints, and lift some weights, and throw a football, I'm choosing A. That's leverage.
He said he'll do medicals with teams interested in drafting him, and he'll have a pro day. As a potential #1 pick, he has the leverage to dictate terms.
My NIL comment isn't specifically about leverage in the draft. It's more about the new reality of college players (and high school), already being "pro" long before they ever get to the draft. All the people screaming "back in my day", aren't going to change that.