Disagree. Let me introduce you to 5DWWBO6HPD (acronym is subject to change). 5 days, 6 hours.

If I dont have any meetings past my 6th hour of being in work-mode (including lunch time), I'm not going to produce anything that won't anger me future-self. The 5DWWBO6HPD also helps you to be actually productive after the 6th hour when the need arises every once in a while and you have to be on "Elon is breathing down my neck"-mode.