I tested a true 8 bit panel, the Asus TUF VG27AQ (au Optronics panel) with my safe AMD Radeon 6750XT.
Migraine and eye fatigue in a few minutes.
Than I'm back to my safe Omen 27q (LG panel) and immediately I felt relief and no more symptoms.
This is a feedback, that monitor can strain our brain/ eyes also if it's true 8 bit.
Probably the backlight type, KSF phosphors, polarization, pixel array, or other triggers, are the causes of our strain with new devices.
So the conclusion is that a good monitor 6bit+frc or 8bit+frc could be better than a true 8bit.