Setup Local-Only Guest Account

I’m trying to find a way to setup a local Plex account within the server that will NOT work across the Internet since my server is accessible from the WAN.

I’ve played with this intermittently throughout the day and cannot seem to find a way.

Any advise?

The managed users work exactly that way if I am not mistaken.

Managed users can connect remotely as well.
There is no ‘local-only’ guest account unfortunately.