The earlier the better. I seem to be able to accomplish the most - with the best quality - in the mornings. Seems to me - at least from my business side - that after lunch way too many people around me tend to lose some of their cognitive skills and become especially emotional or needy compared to their morning mannerisms.
My morning routines might have been a learned pattern. My GF and I first met at work more than 35 years ago. That far back I wasn’t aware of “shielding” so at work I was being influenced by just about everyone’s unspoken desires and emotions. At some point my not-yet-then-GF was assigned to be the first person to essentially open up our business at 5AM. She would frequently come in and find the entire building dark except for my office. I would go into the office at 3AM so that I could have up to four hours of uncluttered space to accomplish tasks and goals before I had to deal with the onslaught of psychic clutter which would seem to grow as the number of staff in the building increased.