Hello humpalumpa: I see this is your first post here on PC. So... welcome to PsychCentral!
I hope you find PC to be of benefit.
I'm sorry I'm not able to answer the question you posed in your title.
This sounds sort-of similar to hoarding behavior to me except that it is apparently "informational" or perhaps "intellectual" rather than physical, if that makes any sense. I can see where some of this probably relates to ADHD... but not all of it. (But then I'm certainly no expert on any of it.)
Perhaps this reflects some combination of ADHD plus OCD?
I see you posted this in the ADHD forum. There is also an OCD forum that may be of interest. Here's a link:
https://forums.psychcentral.com/ocd-trichotillomania/
Ultimately I think what is going on here is something that would have to be determined by a mental health professional... a psychologist or psychiatrist. (I see you did consult with a psychologist at some point along the way.) Perhaps other members, here on PC, will have had some similar experiences & will be able to offer some insights.
Here's a link to an article, from PsychCentral's archives, that discusses ADHD in adults & also provides links to other ADHD-related articles:
https://psychcentral.com/lib/adhd-in-adults/
And then here's a link to an article by our host Dr. John Grohol, Psy.D. on the subject of OCD:
https://psychcentral.com/disorders/ocd/
There is an OCD screening quiz you can take as well. Here's a link to that:
https://psychcentral.com/quizzes/ocd-quiz/