Something sounds very strange about this, with ADHD seemingly a BIG DEAL in your household, as that’s how your child is reacting.
I have one with ADHD (and many other letters😁). It was never a big deal. It was explained, some people have blonde hair, some people have brown hair, some people have blue eyes, some people have brown eyes, some people have ADHD, some people don’t, some people have glasses, some people don’t, sone people are tall, some people are short, some are boys, some are girls. It’s really no more complex than that. If you approach it that way from the outset, it’s no different in their minds to having brown hair or blue eyes, or being a boy/girl just another standard difference between people in a really long list.
Same with medication. Doesn’t make you ‘special’. It doesn’t make you ‘different’. Most people need medication for something these days. I’ve always taken meds, DH always took meds, I’ve got another child that started on their first meds at 3 days old. In fact, not taking meds pretty much makes you the odd one out these days😁. Again, if you make it all a BIG DEAL, this is the sort of reaction you are going to get. Sitting down to watch wanky videos is only going to reinforce that it’s a BIG DEAL.
Mine loves their meds. Just as well as no way they’d be living here if they didn’t take them, utter nightmare, and it wasn’t just them, they lived in a household including siblings so there would not have been a ‘sure, don’t take them, and we’ll all suffer’ approach, that’s not fair to the others. When they were older - mid teens- they got their first pair of glasses and then were finally able to explain the meds, they said it was just like glasses but for their brain, and like the glasses made their eyes see clearly, the meds made their brain think clearly.