Just to share my experience and give others hope - after 2 months my OneDrive is almost back to normal. I have to concur with the advice in this list that the best/only solution is to “wait”. Based on looking at OneDrive online, opening the options menu and seeing if the last option is ‘search’. I believe the migration sequence for me was user A then C then B.
USER C
(share owner)
↕ ↕
User A User B
For User A, after a few weeks of being just a shortcut, I was able to right-click on the shortcut and select ‘always keep on my device’ and all the files downloaded to create local copies. Clicking on the shortcut now opens the local folder that is actively synching online rather than just opening the browser- so this is basically back to normal.
For user B, I can select ‘always keep on device’ and the checkmark turns green, but the files have not started to synch and clicking the shortcut still opens the browser. I assume, as others have posted, that this will begin synching again in a few days (hopefully).
I did clean up and eliminate as many shares and shared links as possible for each user once the file synching was disabled during migration. I have no reason to believe it affected the migration timing, but because we cannot control the timing, reducing the shares has helped simplify the recovery by reducing the number of files that suddenly start synching again.
Microsoft should be truly ashamed of their lack of communication. Good luck everyone.