By default, the BepInEx\config\valheim_plus.cfg is created when you start your game or server the first time. The configuration of an older version of Valheim Plus will automatically be updated to a newer version. When hosting a server, the server configuration file overwrites the client's...
(Note: I did actually pay for OdinShipsPlus but the author never responded to the purchase or any of my follow ups so I was never able to get it unlocked for use on our server and, as such, could not recommend you paying for it. I do hate mods like this with no clearly stated m...