LG TVs may have trouble with certain channels in the 5GHz band known as Dynamic Frequency Selection (DFS) channels. These are the 5GHz Wi-Fi channels from 52-140 on your router that are also shared with aircraft radar.
If the router detects radar signals while using one of these channels, it will attempt to switchto another channel that does not contain radar interference. When this occurs, your connection to the internet will be interrupted briefly, and GeForce NOW will think you have a spotty connection.
You can attempt to workaround this by picking 5GHz channels outside of the DFS range, which are 36-48 or 149-165. Please consult your router manual for information on changing the 5GHz channels.