Also at the end of the day, humans aren't machines. We are goopy meat and chemistry.

You cannot exclusively do hard things back to back to back every 8 hour day without fail. It will either burn you out, or you will make mistakes, or you will just be miserable.

Human brains do not want to think hard, because millions of years of evolution built brains to be cheap, and they STILL use like 10% of our daily energy.