What do you mean with “8k Input. Unfortunately, the SM9970 requires an external "upgrader” box in order to accept an 8k signal.“ ?
As per LG the external Box is only required if you want to play 8k files from USB. The box is free of charge and can be ordered via Customer support. The box has a HDMI and USB connector. If you pleay 8k content from HDMI you dont need the external box.
So my question is are you able to connect the TV to your PC/RTX2070 and use the TV as "display” with full 1:1 8k/60p resolution? If so you can run any 8k Video file or Youtube 8k clips. Right?