When I tried to look up whether ADHD could actually be a sleep disorder, I only found a lot of the reverse: Articles saying that people with ADHD often also get a bad sleep. But I certainly wondered whether the causation might be the other way around.
From what you're saying, sounds like there's evidence that it can be, at least partially?
I have a friend who knows a dentist. The dentist said that when he sees signs of sleep issues (apnea, but he might have seem more) in his patient's mouth, he recommends they get treated. And very often, if the patient had ADHD symptoms, the symptoms went away after getting the sleep apnea treated.
And lastly, yeah. I Also get a lot of ADHD symtpoms depending on my sleep quality/quantity.