I suspect there is still a wide range of likely Chapman offensive scenarios. He could be the shitbag hitter that ended 2023 on a really bad note, or he could be streaky and end up around 110 wRC+ or so, or he could make some tweaks to his approach and pull the ball more on his fly balls and have a tremendous offensive season.
I think the rookie version of Orelvis is going to be in tough to replace what Chapman offers when you factor in the entire package Chapman brings to the table. Orelvis held his own in AAA but far from mastered it as he only produced a 105 wRC+. I think the best course of action would see Orevlis being given a chance to first master AAA pitching so that he's more prepared for the challenges he's going to see in MLB.