Hey – how do I add this custom shop layout for just the shop page? Can I do this at the primary category level, so that each primary category displays its subcategories like this?
You can use WooCommerce builder of WoodMart allowing you to create custom templates for Product, Product Categories pages and other functional pages that are not editable by default. WooCommerce builder is the inbuilt functionality widget included in the builder you use on the site.
Follow this guide: https://xtemos.com/forums/search/woodmart-woocommerce-layout-builder/