Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Q: was this an office update or windows?
A: windows, everything opens in browser and forces files to OneDrive.
You could look into the option of doing a system restore.
You could restore and repair system files. (much of which sounds like compete PC overhaul to fix a simple selection app)
It is incredible to me that Microsoft can sell such buggy software that it breaks and thinks I should spend days uninstalling, reinstalling, and reconfiguring. I only bought MS365 so that I could put the same software on all my computers. Maybe I should have installed LibreOffice instead. I have had it on my MacBook for years and never had an issue with it and it has an app opener just like Office.
Really disappointed.