Headache from me monitor..?

So I’ve been putting off buying OLEDs due to headaches I’ve had while using one in the past.

I’ve been stuck with my old 32’’ Dell 165hz.

I decided to buy a 34’’ WQHD (not OLED) 240hz LG Ultragear and surprise… 5 minutes into it, my head (eyes too) start hurting.

Both have VA panels, I feel like the previous one is even worse when it comes to being brighter overall.

I’m so lost with this, could it be that I just need to adapt to it?