Book 44 was The Woman in Cabin 10 by Ruth Ware.
I wrongly assumed some dark thriller in the woods with a tiny little haunted cabin.... But nope this was a cabin on another cruise ship heading to a tropical paradise. If I wasn't convinced after the last two books after this one I am convinced that my wait listed library books coming available in this order are saying I need (deserve?!) a tropical vacation!
But less about me and more about the book. In the end I mostly enjoyed the book. It had a bit of a slow start for me and I found myself questioning the narrator's reliability which I am pretty sure what the author's goal was but for me if caused more frustration then suspense.