Q: How could I list the (same product) to multiple marketplaces like Amazon, eBay Shopify without it triggering duplicate error message for sku fetch?
A: Listing the same item to multiple marketplaces is possible, but you'd have to first go to Wise Lister --> My Marketplaces --> Create, and create a marketplace for each one that you're selling on. You may have already completed the settings, but now would need to create a "marketplace" which is like a container to house those settings.
Once you've created a marketplace for each of the marketplaces that you're selling on, you'll need to go inside of Sku Fetch and switch the "Workspace" for the first marketplace, go to List & Export settings and click the Get Marketplaces Link under each of the listers and select the marketplace for the first one (i.e. ebay_us). Then switch to the next workspace that you should have created for Amazon, go to the List & Export settings and repeat. Then switch to the workspace you have for Shopify and repeat.
If you need a visual on how to create a marketplace and link it in your list and export settings in Sku Fetch, please see the following, the example is for Amazon, but is the same concept for other marketplaces.
And before you list to each respective marketplace, you'd need to switch the workspace in Sku Fetch prior to listing.