I will try to explain why the shop page cannot be edited. Actually, the shop page is an archive page that just shows the product and it cannot be edited as other normal pages. The same case is with the blog page as well.
That’s why when you try to open it in the Elementor it does not open. So Elementor has a feature of theme builder in wp-admin>>templates>>theme builder>>proucts archive where you can edit the shop page according to your requirement.
Please remember you cannot edit the products but just can add the content before and after the products.
