This is already possible. In the pdf overview there is a layout button on the top right where you can change between compact, list and grid layout.

There is not much I can do as this functionality is provided by mozilla’s pdf.js library (this also powers the pdf reader of firefox).

I just checked, I usually don’t use the app on a mobile device. If you want to highlight text on mobile:

• open the highlight menu
• select the text as if you were to copy it (long press, etc)
• then click on a color
• the text should now be highlighted