To change the shop page title section background, please follow the next steps.
1: Please go to admin->pages.
2: In there, please click the "Edit" link on shop page. https://prnt.sc/1164czj
3: In the page setting field, you can see the page heading background image field.
Please remove the current image or upload your image. https://prnt.sc/1164dde
And for the purchase icon problem.
Could you share your site admin info? We think you installed some third party plugin which is related to the product add to cart.
We need to check in detail. After that, we will let you know the reason.
Best Regards, C-Themes