I realized this about myself years ago, but I don't (think I) have ADHD.
I have always been able to learn faster than most people. No clear reason why. It appears I was just born this way.
But if the Pareto Principle holds, and I'm learning twice as fast as average (estimating for the sake of easy math), that means when I'm a beginner learning the 20% of the skill that gives me 80% of the results, I'm learning like 32 times faster than somebody learning at an average rate who's in the 80% of work that produces 20% of the results, even though they're better at what they're doing. I look like an absolute rockstar out of the gate.
Problem is that my ego has been tied up in that since I was little. Early life is all about learning high-leverage things as quickly as possible, and since that's also when you're forming your sense of who you are, it's a sticky trap. I have really struggled to build the patience for the rest of the grind, where even if I'm still learning twice as fast as average at the harder level, any average newbie is learning/improving twice as fast as me.
The end result is that I'm moderately proficient in dozens and dozens of things, but I'm not an expert at anything except obtaining moderate proficiency.