Server tab not visible in settings

That’s not true.
The method to move the metadata is described here, step-by-step: [HowTo] An extended guide on how to move the Plex data folder on Windows

But you still should solve the missing server tab first: https://support.plex.tv/articles/204281528-why-am-i-locked-out-of-server-settings-and-how-do-i-get-in/