Did an Atlantic crossing in summer of 2019 (not on SS, but on the Queen Mary 2). What I found is that we quickly fell into a daily routine: early morning exercise, late breakfast, lunch, nap, tea, trivia, get dressed for dinner, predinner cocktails, dinner, show, bed, repeat. The days melded together, in this sort of fantasy world where you just do whatever you like, and there's no pressure. Anything you want, you just ask.
It was almost sad when we finally saw the shore. Back to reality.