I am currently listening to an awesome popular science book on sleep called Why We Sleep by Matthew Walker
I highly recommend this book which summarizes the current state of sleep research and its practical implications to most people since most are spending about a third of their time sleeping. If you care about your learning ability, social skills, recovery, creativity or memory, I think it is likely you will find this book valuable.
I am not an expert in this topic but I believe this recent paper is relevant and may derive a result that is more general than Harsanyi-style utilitarianism https://www.sciencedirect.com/science/article/pii/S0304406820300045