A family of Microsoft word processing software products for creating web, email, and print documents.
There is no native method available to roll back that Office update, you would need to uninstall Office using the steps provided on this link first:
https://support.microsoft.com/en-us/office/lifecycle/officeinstall/uninstall-office-for-mac
Then, you can download the installer for your preferred version of Office by scrolling down the long list of Office versions on this link, I think the version you want is available in the February/March section of the table.
https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac