As a person with diagnosed adult ADD, this is one thing I cannot do — manage attention. Medication and meditation help a little, but I probably will never reach the productive capabilities of a regular person. Sigh.
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.
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 or woman who runs through all of this effortlessly, which you’ll never be. What a burden to society!”
All of this is true perhaps, but now I just want to die.
Whilst I didn't get that exact impression from the book, Barkley is known for being "realistic" about ADHD: he doesn't hide the fact that, depending on severity, ADHD can levy a heavy toll on a person, significantly impacting their quality of life. ADHD sucks, but we can make it suck significantly less through good habits, good routines, healthy eating, exercise and, where appropriate, medication and other forms of psychological support.
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?
I know this sadness. However, one thing which has helped me has been the opportunity to work with supremely effective people. It somehow lifts your perspective or shapes your intuition. Somehow monkey see monkey do also works for monkey see
high-level executive function and execution. I didn’t expect that. I thought it might just make the sadness worse. But immersion helped.