>my intense hyperfocus on one thing at a time but also inability to keep consistently focused on one thing for more than a few weeks

Sounds extremely normal to me. I wonder what I'm missing.

For example, suppose a typical person decides to learn a new language.

At the beginning, they are very excited and enthusiastic about it. They might buy a textbook, download an app or sign up for language classes, and spend lots of time on it for a couple of days.

After a week or two, as the tediousness sets in and the goal seems farther off than they expected, they start to shift their focus to something else. After a month, there's a 50/50 chance they completely forget about language study and stop doing it. Only a very small minority will last more than a year.

That's what I'd consider normal. How is ADHD different?

Another example: meditation. A new meditation practitioner may try to focus on their breathing, but then find they usually get distracted and start thinking about something else within 10 seconds.

I have a feeling that if I were to say "I find it difficult to focus my attention on something for 10 seconds without getting distracted", many would reply "that sounds like ADHD." But this is, in fact, quite normal.