> it's also the sort of condition that might sometimes has an instant miracle cure

I assume that by this you mean figuring out some kind of dietary restriction?

I also struggle with a lot of those things (also ADHD) plus other inflammation-related issues (ezcema), and noticed a very specific pattern of fatigue during the day that improves at night. It's hard to tell what might be effective or not since keeping stability in my routine is a struggle, but I've mostly came up empty on explanations/solutions so far.