any sneak peak into the display response time? Only you guys at notebookcheck measure this data reliably, and it is a very good indicator on the perceived smoothness of animations.
It may get brighter if the ambient light sensor is exposed to bright light (i.e.sunlight). Try shining a light on the notch to see if it increase brightness
Apple advertises the new Mini-LED MacBook Pro 14 with a peak brightness of up to 1600 nits and a sustained brightness of 1000 nits, but these values seem to be limited to HDR contents. Standard SDR contents are limited to 500 nits, which is comparable to the current MacBook Pro 13.