When I use external display, I always use screen mirroring and set main display brightness to zero.
Macbook remembers screen mirroring config, but I must turn down the brightness manually every time the monitor is connected.
Is there a way to turn off main monitor automatically when external monitor is connected?
There are similar questions, but the first answer is about clamshell mode, and the second question's answers doesn't match my need. Because I want to brightness down automatically.