BTW I have hard wired my last 2 OLED tv’s using high end audio power cable.
The very recent one, done 2 months ago, an LG G2, I had to take off the entire back shell, as there was no small panel port to access the hardwired power cable like there usually is on LG tv’s.
I have done this twice now, many years apart, and noticed the same thing,,, if the TV is only a 2 core power input, make sure to only use 2 core (figure 8) cable, or if using good 3 core, leave the ground/earth wire disconnected at both ends so it floats. For me having the earth/ground connected at the wall point (but not at the TV, as it only accept positive and neutral) resulted in slightly reduced performance both times.