Dear StevenBergstein,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, please let us cooperate and please don’t worry, we can work together to narrow down and resolve the situation.
Since you mentioned, "Save this new workbook on my laptop (where folders are synced with OneDrive)" you may go to your OneDrive online location and select the file> click on three dots (. . .) and select "Version History" option> and delete the previous /old version history.
Here is screenshot for your reference:
Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!
Sincerely,
Waqas Muhammad