Hello I made .bat and .vbs file for this use
1. For this to work you need to have Dell display monitor manager installed
2. You need to have 64 bit OS or you need to edit path to program
3. Put folder Monitor with files on root of disk C
4. To increase brightness double click "Increase_brightness.vbs"
5. To decrease brightness double click "decrease_brightness.vbs"
You can run .vbs with some program for schortcut for example I Use Razer Synapse.