When I drop a select tool in after a Sharepoint Input (Excel file on Teams), it sometimes doesn't recognize the fields from the input and shows only "Unknown" for the fields to select. It usually clears after I re-run the workflow (though not always), but that can be inefficient.
@a4665zz this will happen every time you attach a new tool with your input file from SharePoint the same thing happens to me while working on other connectors sometimes. Therefore I would suggest you to right-click on select tool and then choose cache and run workflow to save the field settings till the time you complete creating your workflow after that you can clear the cache and run workflow then run the workflow again it will run perfectly fine unless you click on any tool.
Thanks!