All I need to do when reading a pdf is turn it from the two page 'standard' to a single page scrolling. This gets the file to the right size so that I can read it.
This used to be on the top bar, View, and select the option. I can't find where you have hidden it, and neither the help nor the search tools brings it up as an option. Why have you made it so hard to do a basic operation that should be standard?