I'm an examiner for one of the biggest exam boards. I know my subject exceptionally well. Loads of experience. I also have ADHD.
Without medication, I struggle to focus long enough to mark any more than 1 or 2 exam papers. I can't retain what I read at the beginning of the essay all the way to the end, let alone remember the question title. I have to go backwards and forwards between the writing and the mark scheme. I make notes because without them I forget.
With medication, I can work for 4 hours with only toilet breaks. I retain the information from the essays, retain the mark scheme, don't have to constantly switch between the essay and the mark scheme because I just remember it. I work faster and harder for a much longer period of time.
Most importantly, with medication, the work only takes about 1/4 of the energy.
Without medication I can function but I'm slow, stressed and get headaches with the effort required to try to force concentration.
With medication, I function like neurotypical people. It's SO easy in comparison.
NEVER underestimate how hard an unmedicated person has to work to try to keep up with NT. I wish I'd had meds when I was a child.