Sudden non-responsive and "Sqlite3: Sleeping for 200ms to retry busy DB. Sqlite3: Sleeping" messages

I am in almost the exact same situation. Just upgraded Unraid to 7.2 and Plex has started losing connection to each library, with the log showing “Sqlite3: Sleeping for 200ms to retry busy DB“. Some times this persists indefinitely and some times the libraries ‘reconnect’ after a few minutes.