It shouldn't be doing that as long as your PC is running a resolution/graphics mode the TV can display properly.
A few basic things to do:
On the TV, set the HDMI input name for that input to "PC". This basically tells the TV "this is coming over from a PC" and lets it do some backend processing to make sure the signal is displayed properly.
Make sure your TV is displaying a mode the TV knows. If all else fails, force 1080p @ 60 Hz and disable any special processing (HDR, etc).
You can try setting 4:4:2 or 4:2:2 instead of RGB via your GPUs display driver.