Microsoft apps cannot connect to the internet

Basics:
a. what do you see if you create a new user for test purposes and log in as that user?
b. what happens in Safe Mode?
c. what happens after a clean boot?

I.e. process of elimination - maybe.
I've never heard of such a thing..

Great. You'll find, having done the in-place upgrade there'll be one very large update, and then probably a couple of small ones.

Glad you got it sorted. These kinds of problems can be incredibly vexing. You actually got off easier than others who've posted here looking for help. Count your blessings, therefore! ;-)
Best wishes,
--Ed--