I've always been called "smart but lazy", yet before high school I managed to maintain the smart kid reputation. I just happened to be interested in everything superficially and read a lot of books, which worked for grade school level knowledge. It went downhill in high school, where I needed to focus to understand a lot of topics more in-depth and most of the time, I was absolutely incapable of that, and I absolutely crashed in college, where I picked a degree I absolutely hated because of family pressure (yet I still managed to get through several years of that and I'm getting my diploma by the skin of my teeth in May). I've had ADHD all the way through that.

I guess my point is that

a. ADHD manifests differently in everyone

b. some people are lucky to land in their hyperfocus field early

c. ADHD is a spectrum and some people just manifest more severely