I recently, like last night, updated my MBPro 2017 to Big Sur.
This morning, somewhat blithely decided to acquire the latest standalone Office 2021
(not realizing it was basically released today. Here’e the event thread
Purchase MSO 2021 > Click install link > Alert MSO 2021 not compatible with your operating system > cancel install > investigate options refund, reinstall, confirm version purchased
navigate to MS account > Confirm purchase > attempt reinstall > Key Already In Use >
navigate to Order History > attempt install from purchase confirmation > Services and Subscriptions queue devoid of the MSO 2021 purchase & download LINK > two hours on phone with MS (friendly) Support, with mixed messages: Known Issue, MSO2021 for Mac available next month, or install is compatible with Big Sur, but requires Advanced Tech Team Support >>> Requested a refund. Done … Whew! Maybe next time