Thanks, with that hint, I figured out the culprit without quite having to do this. Instead, I mv’d the .kodi/temp/ directory. Because the logs were showing:
2022-11-02 09:34:27.279 T:2773 ERROR <general>: GetDirectory - Unhandled exception
2022-11-02 09:34:27.279 T:2773 ERROR <general>: GetDirectory - Error getting /home/osmc/.kodi/temp/
2022-11-02 09:34:27.279 T:2773 ERROR <general>: GetDirectory - Error getting special://temp/
That solved this problem. Inside that temp folder was a 1.4 GB OSMCBACKUP file, which should have been relocated to the USB flash drive, but hadn’t been. Which means there’s a different issue here…