Code-based sitewide percent-off (closest supported alternative)

You can create an Advanced Discount Code campaign that approximates a sitewide general discount by using a Product Discount (percentage) applied to all products or by using an Order Discount (percentage) off the order subtotal. Example: create a campaign named "Sitewide 10% off (code)" with your desired discount code, add a Product Discount module set to 10% and select all products (or add an Order Discount module set to 10% off subtotal). Note: the platform does not support selecting whether the code specifically targets sale price vs compare-at-price, so this alternative cannot guarantee the exact sale-vs-compare-at pricing behavior you requested.