Moving libraries to a different disk

[jellyfin]

You can't "move" libraries, but you can add a new folder to the existing library.  Open the library settings and click the "+" at the top to add your new folder.  Then the "-" next to the old folder to remove it.

That allows me to add the copy of a library folder and remove the old one WITHOUT loosing all my metadata?!?
It does not sound like it will do this - more like just adding a new and empty folder in which I could then add new movies.
That was not the goal, I want to use a different disk - with all my content and without any other changes (or losses) to Jellyfin!

Like with any other App ...  most just say something like "cannot find folder xyz, please provide the right location" and them you can select the disk and folder where is stuff can be found.