In a somewhat disingenuous "help" article on https://support.microsoft.com/en-us/office/fixes-or-workarounds-for-recent-issues-in-onedrive-36110213-f3f6-490d-8cb7-3833539def0b
Recent issues ("recent"? rubbish)
If you are experiencing problems accessing OneDrive online, you can see the status of Microsoft Office Online Services at the Service Health portal.
OneDrive search is missing some files [PENDING] (pending for a year - Microsoft doesn't care about it)
Last updated: 25 June 2020
ISSUE
Some customers may see a degraded Search experience when using OneDrive on the web or their mobile device.
(degraded = not working at all)
RECOMMENDED ACTION
We are working on the problem, but you can still search your OneDrive files using your computer with File Explorer or Finder. ("we are not working on the problem")