Hold-Spacebar to move cursor: Simulate vertical cursor movement workaround suggestion.
The addition of hold-and-slide on the spacebar has been great. I know Apple has restricted vertical cursor movement.
A workaround suggestion: I don't know if Apple permits it, but
I suggest that if upwards/downwards movement is detected, the cursor moves back/forwards approximately the number of characters in a line, (say about 40 or 50 characters), until you release your finger. It doesn't really matter if it doesn't end up exactly above where it was, all we need is to go backwards in our document quickly!
I know there's not much space for downward movement, but there's a few mm, and perhaps if we slide down a few mm and hold, the cursor could keep moving to the right by approx 40 or so characters per each 0.2 second (or so) until you release your finger. Likewise behaviour would occur when you reach the upward limit of movement.
It would also be nice if when we hold the shift key whilst doing this, it selected the text. It's been mentioned in another suggestion somewhere I think.