The file exchange format provided by the Aspect Finder currently only supports non-variant listings. This can be directly uploaded to file exchange.
From eBay: "Starting June 15, sellers will be progressively migrated from File Exchange to Seller Hub Reports. File Exchange will be fully deprecated by Fall 2021."
For more information on File Exchange and the new changes in full please see:
There is a change for existing File Exchange users:
eBay File Exchange is being replaced by eBay Seller Hub Reports.
You can access Seller Hub Reports from the top navigation bar in Seller Hub:
"If you previously used File Exchange you will find most of its core functionality is now in Reports, including the ability to create active listings reports, sold reports and revise price and quantity reports.
The downloads and uploads of your reports and templates in Reports should be familiar to you from the old File Exchange tool. All commonly used reports and templates are backwards compatible."
Variations in File Exchange require a slightly different format, see "Using relationship fields for variations" in: https://securepics.ebaystatic.com/aw/pics/uk/pdf/file_exchange/File_Exchange_Advanced_Instructions.pdf