Low brightness, iPhone 15 Pro Max

Me and my wife purchased each a iPhone 15 last Christmas.

she got a ‘Pro’ and I a ‘Pro Max’.

Really happy with it, great display but it’s a bit dim under direct sunlight.

Never thought much about it until the other day, sitting outside, complaining I can’t read display.

my wife showed her phone and it was much brighter. I could easily read her display.

went through all display settings, accessibility settings, etc.

both phones setup identical. Both had brightness to max, but a clear difference.

Any idea if the pro max is dimmer than the pro?

or any other settings I might have missed?

Or if this is an issue someone heard of?

(just to add, it’s not dim by any measure. I’ve used it for half year and never had an issue except in direct sun. Still brighter than my old phone. It’s just yesterday was the first time I compared side to side with another iPhone 15 and it’s clearly less bright)

Both our settings as following:

brightness - max

true tone - on

Always on - off

night shift - off

Under accessibility:

Reduce transparency- on

Increase contrast - on

Auto-brightness- off