Still the same problem reoccurring.
I tried your first solution (disconnection of OneDrive...) and it has only worked two days.
then, thanks to another user, I observed that the vault file got corrupted (size reduced to a few kB). I restored the previous version (the one with a couple of MB), and it worked again.
But, again only for about two days.
there is definitely something that corrupts regularly the synced file on OneDrive.
please, fix the issue