Back in the 1970s and 1980s, twice a year I'd drive nonstop overnight MA to FL. The overnight was fine for staying awake. I agree with you about that "tired" window. For me it's an hour or so just before sunrise.
The news said the engineer had recently switched from night hours to days that started at 5AM. I could see the internal clock being messed up, especially this time of year with the shortest days.
The answer would be so simple. Why not just have an engineer and an assistant engineer on each train? Instead they'll spend billions nationwide on equipment to prevent this, and more on workers to maintain the equipment than a second person would cost.
Another example of running on stupid.
I think I saw that they had three conductors on this not-nearly-peak train.
For what they pay these union guys you would think they could substitute another engineer for one of the conductors and have him serve conducting duty at times if necessary.
At least for the very early and very late trains.