So I went from Sony 43x801j (IPS panel) to 50x81j (VA) and then to 50x89j (also VA). I tried different settings, not letting the brightness below 5, disabling all enhancements, RGB and YCbCr color spaces, did not adjust the colors neither in the video control panel nor in the TV.
The thing is I don't get red eyes as from PWM, but headaches and fatigue, which makes the TV almost unusuable.
When I bought the last one the sales told me that, because I had 4 returns, I could not do anymore, so that is it.
Don't know what to try next, what settings or tehniques, whether to update the firmware, etc. The brightness, even at 5, seems a bit high for me, so that could be it, but don't know to to reduce it without flicker.