You can use Plex with LGTV

Plex Players
1

For a year or two I couldn’t get Plex Media Server to work with my LGTV.

I read that they won’t play together and LGTV said the same.

Only by accident I realized that No Plex app is needed within LGTV.

I could use the “Photo and Video” feature (a purple tab at the bottom of the screen on mine) of the LGTV to access my Plex Media Server.

2

Plex Docs → Which Smart TV models are supported?

Unless you have an older or non-4K model, you received bad information.

Plex supports LG 4K/UHD TVs running webOS 3.0 or higher.

The LG Photo & Video app uses DLNA to stream from Plex Media Server.

Monitor the RAM usage on your server. A couple of years ago, there was a bug in Plex Media Server where using DLNA with LG TVs would slowly (over days) consume all available RAM on the Plex Media Server. I do not know if the bug was ever resolved.