What is the difference between Product category and Category in the SHOP app?

[wealthlly]

Hello.
I'm using an app called Spreadr to import Amazon products.
I also want to sell on the SHOP app, but the categories in the SHOP app and Shopify don't sync automatically.
So, I have to manually enter categories to list products that are not listed in the SHOP app.
The strange thing is that some products are automatically listed in SHOP app, but some products are not listed as mentioned above, so I have to list them manually.
Is there any way to automatically list products on Shopify and have them listed on SHOP app?
I would be grateful if someone could advise me.