Many LG screens use 4-Lane DP mode instead of the 2-Lane DP mode for a USB-C cable made of copper this is not a problem but for this type of AOC cable it is a problem because there is a conversion taking place in the cable from an electrical signal to a light signal and this has to be converted again at the other end.
Below is an image of the pin use of a 2-Lane USB-C cable.
In this cable, 4 wires are used for Video (Purple) and 4 wires are used for Data (Orange).
So here you have 1 chip that converts data (orange) into a light signal and on the other side this is converted back into an electrical data signal. The same goes for the video signal (purple).
When connecting a monitor using the 4-Lane DP technique, the 4 wires for Data are used for video as you can see in the picture below.
The Chip must then be able to deal with this to detect that no data but a video signal is being sent this is not possible with the chip that is in the 2-Lane AOC cables. You can try to force the monitor to work as a 2-lane DP display by lowering the refresh rate from 60Hz to 30Hz.
If this does not work then you will have to replace the cable for an AOC cable that can do this namely a 4-Lane DP AOC cable; AK4323; AK4325; AK4327; AK4330; AK4335