Display on Iphone 13 Pro Max

I would check to see if one phone have True Tone enabled.

Adjust the brightness and color temperature on your iPhone, iPad, or iPod touch - Apple Support

There can be minor differences, including settings and hardware. Apple may have multiple sources for their parts. But if you really have an issue it might be possible to get it recalibrated by Apple on one of their machines.

Hello,

Try this:

Go to Settings > Accessibility > Display & Text Size. Then change Contrast, Color Filters, and Reduce White Point and other settings until it is better.

Good luck.