You keep popping up on these threads making wild claims like this. You're like an evolution denier, you keep pushing this weird agenda, but I just don't understand why.
People keep giving you the research and yet somehow you don't read it and then claim there is none.
It is simple to find research about manual work showing 40 hours per week is optimal. It is simple to find research showing that for knowledge workers the optimal is even less.
Last time you you were trying to claim 40-60 hours was an 'optimal' working time for manual labour and linked research yourself which showed that it wasn't.
Why is the concept so antithetical to your world view that you can't accepted it?
There is a huge body of research proving directly the opposite of what you claim, that working long hours leads to an ever increasing drop in overall productivity and leads to more and more mistakes (even deaths). From the 1800s to today, many companies and institutions have researched this and 40 hours keeps being the result. And even less for knowledge workers!
Here's an example of people giving yummy primary research before:
https://news.ycombinator.com/item?id=7089557