Question about LG OLED55GX6

For technical reasons, every OLED could "burn in". However, the TV sets already have very good maintenance tools on board that counteract this.
Static displays over a long period of time are not so good for OLED.
If you don't deactivate anything, the risk is minimal - but you should still know that it can happen if you don't use it properly. I have had a 65E6 since 2016 - no burn-in visible with normal film/TV use.
What you can see is the different ageing of the OLEDS in the area of the black bars when watching films. But that is not a problem there. Also not visible with normal TV, only with test patterns. After all, the TV is advertised as a gaming monitor.
I don't play games myself, so I can't say much about it.