Search the actions for „super brightness“. However I did not spend too much time implementing this and this feature actually only uses public API in BTT. BetterDisplay (I’m not involved in that despite the name) is my favorite app to do this (and much more), but Lunar also seems great. I think they work on a lower level - BTT basically just creates a HDR enabled transparent window which fills the entire display(s), thereby activating the super brightness everywhere on the screen
