[Chen]

If being able to automatically distinguish multiple links on the same page is important, maybe the link "button" could render as a translucent colored letter/number instead of the current translucent filled circle. Or both: a translucend circle with a outlined letter/number inside. This could also improve the UX to select the links in the correct order. (Right now you have to remember which color to press first, then second, ...)  If I need to distinguish links on the same page, i usually write a hint at the designated place of the link, and then place the link on top of that text.

Splitting the PDF to have more than ten links didn't work out well, as the links can only be within the same piece. So in my case i ended up noting down instructions "back 2 pages" and turn the pages manually for some repeats and save the links for the longer jumps. But this felt more complicated than it should.