Fortunately, I do not.
Notice the author of the information I linked. ![]()
Absolutely agree.
Also, shutdown PMS before performing a DSM upgrade. I saw on another thread (probably written by @ChuckPa), that the DSM upgrade does not gracefully shutdown running applications, it just sends them a kill signal. That can also lead to database corruption.
Your assumption is correct. Plex pulls metadata from the files and/or online sources and stores it in the database.
Some or all of the information in your database might (will) be lost during a recovery/rebuild. So, Plex will have to rescan your media and redownload data from online sources. However, it will not modify your files.
If you want to try repairing the database first, this post mentions copying the db file to another platform - Windows/Mac/etc - to attempt the repair.
That would let you work in an environment more familiar than Synology CLI.