I agree it depends on the doctor, as I don’t think there are established protocols for dealing with such a thing. I do know that this is the reason it’s a controlled substance; because it can easily lead to abuse since the urge to take higher and higher doses is common and those higher doses pose significant health risks over therapeutic doses. So, a good doctor shouldn’t “punish” you for it, but rather work with you to solve the problem so you can continue to get the treatment you need.
As to possible solutions, you must first really want to solve the problem. That is, if there is any part of you that wants to continue taking high doses, you are less likely to accept any solutions. You seem to have the desire to stop, so that works in your favor. But do some self reflection and be honest with yourself.
Here’s one idea that can help: Get one of those monthly pill organizers (most are weekly, but there are monthly ones, which you may have to look online for). Fill it up right away with any new filled prescription. It won’t keep you from taking extras, but it will make it immediately clear that you’re stealing from your future and how much you’ve done so. When you just take from the bottle, it’s not as easy to understand how much you’ve done so, or what the impact might be. This helps because we ADHDers aren’t good at thinking about future consequences, but with a strongly visual reminder, it’s more likely.