REPLACE DATA SOURCE acts on the whole workbook.
Make a copy of your workbook. In the copy, do REPLACE. Then right click on the tab of the sheet you want hooked to the new data source. Select COPY.
Now go back to the original workbook. Start a new sheet. right click the tab. Hit PASTE. The sheet from the copy workbook will get added to the original workbook, and it will be hooked to the new data without impacting existing sheets.