Local clients not finding server unless internet is up

So basically… no matter what I do I will never have offline Plex on my smart TV or Chromecast streamer. Wow. Simply Amazing.
I think it’s
A) Patently absurd that this is even an issue in the first place
B) extremely unprofessional that users need to be directed to a 3rd party blog post to even attempt solving the issue
C) INSANE that there’s actually no solution.

This whole thing is ridiculous, and if this had come up during my trial, I would never have paid for a license of any kind.

Bitterly disappointed rant aside, this really isn’t such a big issue since the internet is OK most of the time, and it works well enough for the moment to keep me on plex and not some other software.
But, what DO the experts here suggest doing when the internet flakes? I’m not able to unplug my server and connect it with an HDMI to the TV…