Oh, I think I finally understand what you are talking about. You mean when you press the "up arrow" at the top or bottom of the scrollbar like the guy here
<img width="91" alt="Screenshot 2025-01-04 at 19 51 22" src="https://github.com/user-attachments/assets/f74a19d5-1c43-4f95-afa3-b66b39135dc1" />
and keep it pressed, the scrolling events are only generated once per second, right? It's indeed a little too slow (though I personally use a mouse wheel instead anyway).
I'd say scrolling by 1 line may be intentional so you can get the view exactly to the line you want, it just could be a little faster.