This demo of products below has 2 columns spanning full width of page. The above 'cover image' is inside content area. Ideally, you can keep the 'Shopping Cart icon' and page 'Headline section' enabled like seen here, but here you can choose to keep it hidden too.

Note that below products thumbnail images do not appear to stretch to full width of the box's size because in WooCommerce > Catalog its width has been setup as 280px. If you want it to resize to fit in the box, then you should put in 425px as its width.

This page was built using a single WooCommerce shortcode, the settings for which are done as easy as point and click from the page editor.

Default standard shopping page is this > Shop Main