I have tried various methods found on the internet, including xbacklight . The main issue is I have no folder inside /sys/class/backlight.
Usually others happnened to have a folder like intel_backlight and inside it they had other files which they could change to change to backlight.
But I dont have any folder in it.
It may have something to do with the graphic drivers as the sometimes screen tearing happens when watching youtube videos as well.
Thanks in advance.