Earlier quoted context omitted.
I'm in the same boat; diagnosed with ADHD-PI (UK, so we don't use the term 'ADD') as an adult. I've improved vastly thanks to medication and good routines but it remains a constant effort, and improvement is a continual process. The book Taking Charge of Adult ADHD by Russell Barkley helped me significantly.
Just bought and read the book. For me, it was fantastically depressing: basically it says: “OK, so you have ADHD. Sucks to be you. Go through this huge laundry list of these and those things to do, don’t forget to take your medication, find a mentor — assuming anybody would want to deal with you, and who could blame them? — and if you are extremely lucky, and with heavy effort, maybe you can become half a normal man…
It's a cliché, but comparing yourself to others is a bad idea in this domain. I have yet to meet an ADHDer who makes these sorts of "upward comparisons" and derives anything useful from them; they typically just exacerbate feelings of inadequacy and hopelessness.
Personally, I know I might never be as effective or productive as a person without ADHD is capable of being, but I can be the best version of myself — it's fruitless and unhealthy to ask more of yourself than this, right?