Bigger, yes. Though they both fit the bill as 6’7ish tanks with strength and explosiveness.
Zion might be more explosive, but I don’t know about “much more”.
LJ was something else. #1 pick. I remember LJ said there was supposed to be a Converse commercial with Larry Bird and Magic Johnson as mad scientist doctors combining their names while “creating” next great player in an operating room, which is why he signed with Converse as a rookie. Different forms of media, but the hype was very much there with LJ too and deservedly so. He was a specimen too.