I typically start work at 7:30. I have about 2-2.5 hours of actual, mostly undisturbed productivity. Early in my career my managers thought I was a genius because I knew everything. I did - because I read stuff.
Nowadays I’m a boss guy, and I’m fully up to speed and ready to go at my 9:15 standup, and half my colleagues are running behind to make the meeting.
Note that I’m not a “morning person”. I hate waking up at 5:30. But my kids need to get to school, my wife tends to start early and I don’t see a point in lounging around. People would be better off focusing on taking care of themselves instead of trying to make laziness some sort of protected medical condition.