JellySearch

[domi]

Change JELLYFIN_CONFIG_DIR to point to '/config/data' instead of '/config'

Hmm, tried that and got the same outcome. 

I believe you are one folder too deep, the final path inside of the container for the database file should be /config/data/library.db.

If you remove the JELLYFIN_CONFIG_DIR environment variable and mount ./jellyfin-folder directly to /config it should work.
./jellyfin-folder should contain a data folder.