I'm 6'0" but with more of my height in my torso (my sitting height is taller than my 6'2" son with his long legs). Yeah. I normally have sunglasses on but I lost them just a couple of days ago, so that almost certainly made it seem much more apparent. The windshield interior also has a little haze built up on it making the situation worse too.

This dash is not leather so maybe that is a little more shiny. Dunno. In any case there is clearly a difference between a dark and a little dash. Even out Lexus SUV with a tan interior has that part of the dash in a black color.

 

I also noticed the glare from tan interior of my 991.1. I solved the problem by ordering a dash cover (Black) from Dashcare.com, a California company division of Seats manufacturing.
It was $45 and arrived within 2 days of ordering. Fits pretty well, with cutouts for the vents. It comes with adhesive strips, but I choose not to use them, so I can remove the cover when showing the car.