[GeoffR]

It is possible to patch the firmware to add a large top or bottom margin when reading ePub books, at least one other person has used that to avoid an area of screen damage near the top of the screen.

But from your photo the problem is in the centre of the screen, so you would have to add a very large margin and would only have the use of about half the screen for reading. That might cause some problems with displaying images because the usable area of screen would be wider than it is tall.

Edit: If you are sideloading ePubs with Calibre, i.e. they are DRM-free, then you can add a margin by modifying the book's stylesheet instead of patching the firmware. This is something that can be set up to be done automatically for books sent to that specific device, without affecting books sent to another device. You might want to try it this way before patching to see what it will be like.

Does that sounds like something that would be useful?