I don't know what the state of this is on Android, but iOS 13 lets you grab the scrollbar and go immediately to wherever you want in a document.
The scrollbar doesn't show up by default, so it's a 2-step operation. Scroll a bit to make the scroll indicator appear, then grab it and scroll faster.
Works well but I doubt many people are aware of it yet. People just assume you can't grab the scroll indicator in iOS since Apple took that feature away when they first launched the iPhone. Scroll bar has been non-interactable for the last 12 years of their touch devices.