> When you map “white” down to gray, you have to drive the LED backlight brighter for the same perceived screen brightness

So that's why Lunar[1] reads a much higher brightness and makes all external monitors as bright as ten thousand suns when HDR content is played.

I wonder if there's any way to detect this and read or compute the SDR brightness instead.

[1] https://github.com/alin23/Lunar/issues/86