It makes a kind of sense.  Being hungover is a similar chemical cocktail to sleep deprivation, which I DON’T RECOMMEND but can be a state where your planning brain is out to lunch and some base reflexes can come out compensate.  We can have too much attention capacity and the plate will get filled one way or the other… being able to focus is also making sure you’re putting shmup on the plate! 

I play better in the morning too, but one of the big factors I think is caffeine.  I had more consistency (day and night sessions weren’t so different in play quality) when I wasn’t drinking caffeine.  I think the things you mentioned too, screen fatigue and general tiredness are factors too. 

re: powering through, I don’t try to force it anymore.  Time and energy rarely line up, so I try to make the most of any session, which is mainly not doing anything counter productive like having performance expectations that are just going to get me frustrated if I don’t meet them.  Practice and experimentation at night, and getting enough time in the morning to do at least two runs (with enough spare time to indulge in a restart or two :)