Yesterday I applied updates to both Acrobat Pro DC and Office on macOS 11.6.2, so I'm not sure whether is regression was caused by Office or Acrobat.

Office was updated to version 16.58 (22011201)
Acrobat was updated to version 2021.011.20039

Now:

1. When I launch PowerPoint, I get an error (see attached image): PowerPoint couldn't load the add-in /Users/admin/Library/Group Containers/UBF8T346G9.Office/User Content.localized/Startup.localized/PowerPoint/SaveAsAdobePDF.ppam

Indeed: the SaveAsAdobePDF.ppam file no longer exists.

1. Word no longer contains the Acrobat add-in in the ribbon. If I open User Content.localized/Startup.localized/Word/linkCreation.dotm and enable macros when prompted, the Acrobat add-in loads into that document, but that's it. It does not load into any other documents.