+1 This fixed my issue too!
I could not stream my movies over my local network, they would all go over the plex relay capped at 2mbps with horrible quality and buffering (verified by losing access to my library in the plex app when I turned the relay feature off in the plex network settings). I wasted so much time digging through the settings in my Apple TV app trying to see where I could give it my server's IP address directly.
Once I flipped this Host Network switch in the TruNas interface, my movies play without issue (presumably over my local network). Bonus, I also found the setting to take advantage of my server's GPU here as well:)
