I'd be a little skeptical of a claimed targeted treatment, but maybe that's just me.
Have you ever had a sleep study (hooked up overnight to an EKG)? This is standard for diagnosis of possible sleep apnea and narcolepsy. I actually came across the term Idiopathic hypersomnia while researching my own sleep problems -- like you I've always been a night owl, stayed up late reading under the covers (may have ruined my eyes that way), watched Letterman and Conan at work back in the day and often worked a 12 to 12 schedule, stopping by the pizza parlor on the way home to pickup any unsold pizza order for $1 (they closed at 1AM). I don't have your other maladies or any symptoms that might be attributable to them, just the sleep issue. My doctor suggested I might have sleep apnea and recommended a sleep study, but I have no insurance and the test is expensive, so I keep putting it off. (Also, I'd never be able to tolerate a CPAP machine, so a diagnosis of sleep apnea would bring me no real practical benefit.)
In my own case, I suspect narcolepsy type 2 is more likely than sleep apnea, and it can be treated with medication* so I really hope I can arrange the test before too much longer. My mom had a similar test done a few years ago and Medicare covered all her expenses. With neither insurance nor Medicare, I don't know how I'm going to swing it. It's likely to cost over $1000 and maybe a lot more without coverage.
*Ironically, the usual treatment is Nuvigil, which I believe is one of the drugs the WH physician was distributing like Halloween candy. So ass-kissing Trump minions could get all they needed for free, and I can't get it at all without a Rx.