I am a shopify parnter company, and I already have this solution ready.
I have been selling the same application to several of my clients.
Let's have a chat so that I can give you a demo. It supports various shipping partners, returns, cancellation, refund, Reverse-pickup, delivery management, tracking, orders.
We can setup a version for the features, that you would need.
Also this is a dummy bid, we can talk about the features, so that I can give you the best costing.