so 3 hours of focus per day? That sounds like a medical problem to me, so if it really is that then it is understandable. But thats not the vast majority of people like you mentioned (although the vast majority does suffer from focus problems).
Have you tried fasting or other things to help try to narrow down the cause of your headaches? Have you had extensive blood panels (a full panel, not a simple one your doctor will give you... I think you have to order the FULL full ones online). A lot of my business partners and people I work with do that biohacking stuff where they try to find out every way to augment their body. They do weird stuff like fly to mexico to get stem cell injections, etc. Ive never been into that, I just take a multivitamin, but it's possible there is something you're deficient in that could be found out? I'd be almost certain there is SOME combination of SOME THING on this earth that would fix whatever it is, even if it's not well medically documented.
I know a number of people with severe neurotic issues, like TRUE neurotic issues, and fasting is really the only common denominator of what has helped them more than any medicine. People have thought fasting was fugazi woo-woo for the longest time but I believe medical science is now catching up as to the benefit (harvard studies, etc). Ive fruit fasted for 45 days once and healed my gall bladder after the doctor couldnt explain what was wrong with it and their only option was to cut it out.
My mother is similar. We both don't have that much energy and seem to tire quicker than most people. I've tried some things over the years, done paid blood panel (not the most fancy one you could get), fixed my sleep, excercised etc. I think it probably comes down to below average genes.
The headaches themselves are from coffee (ab)use. But, without the coffee, I would succumb to fatigue earlier.
Right now, it doesn't matter that much. Luckily, through some smart choices (always aggresively going for the highest paying work I could get) and through frugal living, I've FIREd and now live a life of leisure, which seems to fit my disposition quite nicely. Not everyone was made to be a star.