DK> volume outside the container. For that, I need to know where the config
 DK> settings are stored - ie, the settings you configure with mystic -cfg.
 DK> Any help would be appreciated.

Looks like the /mystic/data directory is what you're looking for.

There is also the file /mystic/mystic.dat

--- Mystic BBS v1.12 A47 2021/12/24 (Linux/64)