Is it possible (without creating a custom cart page) to block clicking on an item in the cart so they can’t click on the item and it takes them to the product page?
Probably not as Wix Stores is a Wix app and the add to cart button is part of the design.
As this issue is not really code related you would be better suited reading through Wix Stores own support pages for it or contacting Wix Support themselves.
https://support.wix.com/en/wix-stores/setting-up-your-store
https://support.wix.com/en/about-wix/contacting-wix-support