I'm not really sure if "system/user data" includes all my movies I downloaded but it seems that it does... in which case my movies take up roughly 19GB of that 42GB... so I am thinking that yes it seems high in your case... hope that helps...
Same, exact amount for system, on my Verizon branded Note 9.
IDK if that's "a lot", but I think it's because of the two partition (A/B) system update logic or whatever is called.