I have been using the new pdf viewer and love it, but comments and highlighting take up a lot of screen space because one is on each side. If they were both on the left, this would leave more room for reading the pdf.
You can close the comments tab by clicking the comment icon in the upper right. You can close the left panel by clicking the arrow in the bottom left. After doing this, press Ctrl + 2 to adjust the zoom level to the page width.