Name one RHD who is on the trade block.
You can’t just go to a store and buy a defenseman with your draft pick just because it’s high. You have to first identify a good player that a team is willing to part with. Almost every single team could use another RHD, and zero teams have extra that they can afford to lose.
Any trade would totally screw over any team who isn’t rebuilding, and there’s only two teams doing a true rebuild. So if the player you want isn’t on San Jose or Chicago, he’s not available for a draft pick.