This batch file works for modern Click-to-Run (sometimes called ClickToRun, Click2Run or C2R) based Office installations (note the odd lowercase microsoft shared which indeed is the actual directory name):
if exist "%CommonProgramFiles%\microsoft shared\ClickToRun\OfficeC2RClient.exe" ( "%CommonProgramFiles%\microsoft shared\ClickToRun\OfficeC2RClient.exe" /update user ) else ( echo could not find the Office Updater )
This for sure does not work for MSI based Office 2013 and lower (which are updated through Windows Update anyway). Since I only have 2021 online (Click-to-Run) installs and higher to test with: those work fine.
The Wiert Corner - irregular stream of stuff 