I have found two possible plists that might be at fault. Both are located in ~/Library/Preferences

com.microsoft.OfficeConverter.plist
com.microsoft.openxml.chart.app.plist

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365