Bigger screen (which for many is a minus not a plus), an extra 4GB RAM (still seems absurd to me that we need this much RAM on a phone) and more capable/additional auxiliary cameras.
I suppose the charitable take is that £700 feels like a pretty good deal for the non-Pro one.
I guess I'll stick with my Pixel 5A.
https://support.google.com/pixelphone/answer/11833075?hl=en
This just happened to me after 1.5 years of usage of my Pixel 5A.
Luckily Google extended the usual 1-year warranty to be 2-years to give free replacements (which I took advantage of and in fact was given a free upgrade to a 6A)... But be prepared for your phone to die out of nowhere.
That being said I did want the better camera on the pro.