> complaining about open offices and useless meetings; do all of them have ADHD?
There's a commonly used diagnosis survey you can check. It should give you a better idea than this.
> ADHD developer and a regular developer
To give you one example (but this won't cover all cases / everyone's experience), if you're in the bathroom and think you need to change the toilet roll, then proceed to forget and remember it again 6 times before leaving the room, then head for the toilet roll stash, forget about it and go make yourself a sandwich instead... and that applies to almost everything you do throughout the day, you're probably in category 1 not 2.
For medication, another example would be when you take stimulants and get relaxed, less nervous and feel like you could finally go for a nap...
What I'm saying is, some people may be experiencing smaller issues for the same reason, or they may just not be satisfied with their environment and are able to act on it, but there's some threshold where it's not even the same category. If you don't know what ADHD actually is, maybe check the experiences written by people who do struggle with basic things daily while seemingly highly functioning otherwise? There's a number of subreddits where you can find them.