I didn't get diagnosed with ADHD until I pursued it viciously as an adult. I always wonder how I could have actually been treated as a child instead of dealing with doctors arguing if I was ADHD or ASD, as I could only be given one label back then (2000s). Good to see that there is now research being done on this and that we are moving forward finally.
Do you still have the pdf of the paper? I couldn't access it through the links you provided and it's not on Sci-Hub yet. It looks interesting and I'd like to read it :)