How do I change cover on my book I published in Apple Books??

seriously trying hard not to just dump Apple books as using their login and system to upload is ridiculous compared to Amazon KDP - but I'll try my question.

I've uploaded an EBook - I want to change covers. It doesn't allow this for some reason.

When I click my book cover in My Books summary where there is the links for Rights and Pricing and Setup Tax etc.

I scroll down to the book where it says - view details.

All I get is a message saying Epub 3 and embedded content - java script.

So I cannot change my cover or anything - tried on Safari, Chrome and Edge.

What am I missing and seriously - Apple - make it easier - if you don't want books just delete the **** app. Or default to amazon.

Frustration over.