Hi that test does not compare the screen in the M1 MBP and M1 MBA ? In the display section of the MBA review it says
The color accuracy of the panel is excellent in our tests. The color tests as well as the grayscale are significantly better than with the Windows competitors. The display is therefore very well suited for photographers and others using applications that are dependent on color accuracy.
In your original comment you said
I have looked at a number of examples of black content to check before I posted my reply and I don't see the red glow that you suggested exists.
They must be using slightly different screens for the MBA and the MBP M1, so perhaps there is a difference in contrast, but all the reviews that I have seen, the only difference mentioned is the brightness. Anyway as I have said the screen is better than in my 2016 MBP, so I am happy.