Copy the database folder over there. Put it into the same folder structure that it has on your C: drive.
Then pretend to have moved all the other data of your plex data folder as well and make the registry change as explained in [HowTo] An extended guide on how to move the Plex data folder on Windows
But never start Plex server with that registry change in place.
Instead, just use the debloat batch file from above, followed by the repair bat file from DBRepair/Windows at master · ChuckPa/DBRepair · GitHub
Once that is done, copy the de-bloated and repaired database files back to their original place on C:, overwriting the bloated ones.
Then remove the new registry key again.
Only then start Plex server.
