Hello,
My name is Chris and, as you can see from my profile, I have many years experience on Excel/VBA and also on online marketplaces (ebay, amazon, etc). The program you need will be created as an Excel add-in, which will ask you to select the "source" ebay csv file and then it will create the corresponding shopify csv file. I will need a representative sample file (csv) created from eBay products and another one from shopify, in order to have an idea of the products (simple or with variants, and the kind of these variants) and also to get some extra info needed for the shopify file (like Google shopping settings, tax code, gift card, fulfillment service, etc).
Looking forward to hear from you,
Kind regards,
Chris (chriskerpini)