I suggest seeing a neuropsychiatric specialized in ADHD diagnosis, there are tests that can be used to diagnose ADHD no matter your IQ, by for example looking at impulse control - you can be diagnosed with an IQ at the edge of testability, that is certainly past the meaninglessly high point.

It's true that it's more difficult with a high IQ, but looking at impulse control tests, variations in subscores, IQ-like tests to detect invalid subscores, attention direction tests, as well as your personal habits and talking to people in your surroundings/who you grew up with, it's very much possible for a confident diagnosis to be made no matter the IQ.