This feels familiar.
I went back to school at age 48 and it amazed me how younger people could do so much and so well. I'm amazed at how people can be so efficient. Those same people some just 10 years younger than me worked full-time jobs and went to a full schedule of classes.
I'm terrible at time management. At school I tried to start every assignment the minute it was assigned. Yet I was still working on it five minutes before it was due.
Eventually I figured I needed time to relax so I created a block of time only for school. I do better when it's evening or night so I blocked off 7pm to 9pm. That also allowed me to eat first I found eating later didn't work since my mind didn't work without food younger me could have plowed through the hunger (I'd often go days without eating as a 20-something).
From the article the two practice-time peaks make sense. Maybe I may do just as well in the early morning as I do in the evening. That would free up a large part of my day. At school I found things like laundry, grocery shopping, any small task was sacrificed to make up study time.