The average American commutes ~30 minutes each way [1]. Given a 9-hour workday (8-5 or 9-6), and 8 hours of sleep, that leaves 6 hours to eat breakfast, dinner, and get ready for work/bed plus occasional errands/exercise. This is also really only applicable Monday through Thursday, because Friday night and Sunday give you more flexibility. I'm just pointing out that for many people, there is quite a bit of time.
It is better to start with a healthy amount of sleep and figure out ways to optimize your other time, rather than thinking about what you want to do and using your sleep time as an adjustable lever. The truth is that if you feel like there is nothing else in your life besides work while you're getting a healthy amount of sleep, you need to make other life changes (if you have the option). Limiting your sleep will just ruin your mental and physical health.
[1] https://www.washingtonpost.com/news/wonk/wp/2017/02/22/the-a...