I’m talking from a scouting perspective here, not pure stats. Obviously this is somewhat anecdotal, but Rahk wasn’t afraid to take threes when he had the opportunities as a freshmen. He was aggressive offensively whereas Z was very timid all over the court. There’s also the fact that Rahk’s form was much much better.
It doesn’t preclude X from ever improving, but I think it’s clear he was a bad shooter the last time we saw him (and the insider chatter about his shot over the summer has not been glowing. It sounds like he has not improved).