I have a somewhat rarely diagnosed circadian rhythm disorder called delayed sleep phase disorder. It is difficult to get diagnosed, especially as sleep clinics have been targets of private equity firms which convert them to CPAP shops which only diagnose sleep apnea and whose patients never interact with an MD. However it is likely to be underdiagnosed given the stigma around sleep challenges, at least in the sense that if you make any effort to get enough sleep with such a sleep disorder, you tend to be pegged as lazy, irresponsible, unreliable, etc

In any event, I agree with something implicit in the article, namely that most people have a degree of this, but the severity is variable. Mine has been fairly extreme, and while diagnosis enables disability accommodations, it is very fraught navigating most workplaces with this particular disability and you are essentially forced to choose between having any kind of upward mobility and getting enough sleep at night.

Thankfully the past two years or so I've been getting much more sleep since optimizing more for that. But anyway, if you are navigating sleep challenges you should get a sleep study, sure, but also be aware that your local sleep clinic is in all likelihood only nominally a sleep clinic. That is, it does not know how to diagnose and treat more complex sleep issues and probably doesn't want to.