I want to know which of my pages have the highest bounce rates so I can fix them. Ideally, I would also know if they are bouncing on desktop or in mobile. Is this something I can find out in Google Analytics?
Yes, you can see bounce rate for each page and if it's mobile or not!
1) In your GA you need to go to Behaviour > Site content > All Pages
3) When you start typing "mobile" you can see that there are different options. The Mobile (Including Tablet) is what you're looking for.