Samsung display causing eye strain

Hi folks. I'll begin with the phone models that I have had - Nexus 5 - s8 - s9 - P6a - s23(Got it this week). I have noticed eye strain & compared with my current s23's display to that of P6a's & have realised that the colour/contrast/saturation was much more subtle in non-samsung phones(incl. iPhones) which is causing eye strain & mid headaches.

I have already switched to the natural display & eye comfort shield (without a doubt, Google's & Apple's night light is better).

How do I make the display less contrast/saturated & easier on the eye?