You can reduce/minimize Plex‘ dependency to have an active network connection. However you won’t be able to use it well in a no-internet environment.
There’s an exhaustive post in the tips & tricks section discussing these dependencies and how to address them.
I’m not sure I understand your question about DLNA. You can activate the DLNA server of your PMS. The dependencies are the same as running DLNA still needs your server to run… and that’s where most of your dependencies are.
