I am now and have in the past been in this sort of position, albeit not with an existing completed degree under my belt, just a simple one-year continuing-ed diploma and years of sporadic career experience.

I went back to attempt to complete my CS degree on the basis that I figured I already had learnt most of what I would learn anyway and might as well both prove to myself I can do it, as well as get the credential for whatever it was worth. This was when I was ~27, and hadn't been diagnosed with ADHD yet. I discovered that I was absolutely capable in theory, but that the hard part wasn't the material, rather it was doing rote tasks to get the grade regardless of that grade's relevance in the field. I found myself completely capable of doing the homework and understanding, writing various persuasive essays, and intellectually applying myself, but failing horribly when it came to anything my brain identified as less interesting than any other subject matter, and I had effectively no control over that (unmedicated). I also had no ability to be on time, and once I realized that I was effectively wasting time and money trying to pass through the Type A Gen X career gate defined largely by the binary of having a degree/not having a degree, I opted to not continue. It wasn't about learning anything, it was about a checkmark, and I didn't and never have really internally care about checkmarks.

It would be the easiest material or courses that I'd bomb the hardest at, forget to do entirely, or simply not be stressed enough to do well; basic trivia, courses where 50% of the grade depended on labs where I'd be required to draw diagrams by hand, exams that required writing Java for 3 hours in pencil. When other students were anxiously scribbling away, I just flatout wasn't worried about it and just kind of spaced out for a while wondering why I was trying to bother. Exams require anxiety in some form or fashion, and in many cases I could not provoke that in myself. In some cases, I indeed didn't do so well on an exam either because I couldn't burn it into working memory well-enough (never having learned a study practice that worked for me) or I overslept... as a 27 year old adult.

Now, I'm once again out of work, considering going back to school for... something, but I have all that exposure in the back of my mind. Even now that I'm medicated and otherwise quite happy, I have doubts that I'd be able to succeed in any type of educational institute unless every facet was perfectly aligned for me. Having money on the line or an abstract incentive aren't sufficient rewards to have a functional impact; I need to find it intriguing throughout and believe it's useful, or be fighting my way out of a tangible corner, of which I'm not in and don't naturally panic about being in.

I think you might be misreading this person. If the point of homework is to learn the subject, while tests assess your understanding of the subject, why do the homework if you already have a strong grasp on it as soon as the teacher explains it? If the point of doing homework is to keep you busy, there are better things to do with one's childhood. Unless the disability you're referring to is that they never learned how to struggle (because no struggle was offered)...

Yeah, I was labeled twice-exceptional and medicated for it, but there was also this general thing where I felt like I was special for not needing to study and that it was something to take pride in, which I don't think is inherent to ADHD. I have some friends who also have ADHD and are decently smart, but they have always taken pride in being hard workers, and have come out much more academically successful than I did.