Sorry to jump on this thread but I have the exact same problem. I log in at least once a week to onedrive which is shared from my sister to myself for work, and last week (Friday 6th) I logged on to find that it had deleted all files and data from 28/03/24. I was as though I had just logged back in in March! I also had access to the current one drive files on my phone but not on my laptop or my macbook. I have resynced and done all that I can find online to help including my sister resharing the onedrive files with me again, but nothing is working.
Onedrive is working perfectly for my sister, it is just on my log in that it will not work on laptop or macbook.
Seems odd that it is the same date as the person posting this thread?