set monitorList to {"LG UltraFine (1)", "LG UltraFine (2)"}
set brightnessValue to 0.7

tell application "System Preferences"
	reveal anchor "displaysDisplayTab" of pane "com.apple.preference.displays"
end tell
tell application "System Events"
	repeat with monitor in monitorList
		set value of slider 1 of group 1 of tab group 1 of window monitor of process "System Preferences" to brightnessValue
	end repeat
end tell
quit application "System Preferences"