My Pro 2 screen seems darker than my Pro 1. I have to set the brightness to about 75% to have the white on this forum be bright. I think on my Pro 1 I only needed to set it for the screen to be bright.
The adaptive screen brightness may have been tweaked for better battery life. You can turn this off and test it by going into the advanced power plan options. I keep mine on when using battery, and off while on the charger typically.