For me personally, it's too difficult to say who is for sure the best prospect between Tre, VJ, and Ace. So I really don't want to give up assets to trade up.If the Jazz have a preference for who they want outside the top 2, they should do that deal, or offer a young player instead of #21. Then do the exact same thing next year.
At the same time I think it's likely that one of those three is significantly better than the others in the end, and if the FO figures out who that is then I think trading up makes sense.