I want to filter orders on my Shopify Dashboard that are fulfilled but not delivered yet. We are using USPS which is integrated with Shopify. Individual Orders have that information whether the order is delivered or not but I can't find a filter on Order Listing to do that.
You cannot directly do that in Shopify. As you have mentioned, the Shopify orders page shows information for individual orders. To have a list of all orders information, you will have to use an app like Multi Carrier Shipping Label, that will show the status of all your orders under a single dashboard. Check out the image below.
Will this help in your case?