Wouldnt you be less efficient with less sleep ? For a startup you should improve sleep quality

Generally yes, and I definitely am an advocate of getting enough sleep and good quality sleep.

Regarding "sleep more to be more efficient"; Hard to say without visiting a parallel universe. But in this specific case it was really about having enough hours in a day. Most of the work did not require me at my sharpest. If I was in the same situation today, Claude would be doing these menial things for me and I'd sleep more. But we didn't have Claude then.

It was a tech startup that I wanted to build without any outside money. With investments of course I'd just hire more people. I had luck and perseverance, and everything turned out great. I had 100% ownership and sold it for private equity. Now I only work because I like solving tricky problems, and not working gets incredibly boring after a while.

Yes, but this is sadly a lesson most founders (especially american ones) need to self teach.

I certainly did and struggle with both sleep and stress induced anxiety, 9 years after my founder burnout.