Hello,

We are Glad that one of your issues is resolved.

To change the shop page background you need to Edit the shop page and set the image for page title from there.

Screenshot for Clarification: https://ibb.co/zGKqtMB

Try setting the dropdown width to full-width from there then clear cache and check back.

Screenshot for Clarification: https://ibb.co/zNwWcxM

Best Regards.