Spy on ebay sellers - Who are dropshipping from amazon -- 2

Basically, people are selling items from amazon to eBay. I want to create a tool that lets me compare those eBay sellers items with amazon, and if it matches, it should give me a list of URLs. So it is kind of like spying on them. In simple words, the tool should compare those seller items on amazon, and if it matches, it should fetch the URL. I want the tool to be able to do 1000s of items in one go. I think you would probably require web scraping knowledge. Message me if you totally understand!
Check out this software something like this --> https://youtu.be/76VaYLiHXjw.
I want something very similar.
I will have the source, and the freelancer has no right to use the tool they gave for any commercial business; I will be the only owner of the tool, and I can do whatever I want with it.