I tried re-installing kali linux for other reasons, and still don't see it

For some reason, running latest Kali linux, brightness slider is absent in the top right right-click menu where it usually is, like in my friend's laptop.

It's frustrating because I'm not able to change the brightness to get better battery life on my laptop. If someone could help me with it, that'd be great.

Perhaps it's best I mention right away that although I was able to install xbacklight by 'apt-get install xbacklight', the commands show no output and don't reduce brightness for my laptop at all.

I also have seen forums explaining how to manually edit /sys/class/backlight files to change the brightness, but I don't have any further directories to find that file from. The /sys/class/backlight folder doesn't have any file or subsequent folders inside.

The 'Battery & Lock' tab inside the settings app is also not there, and there's no option to change brightness in the Power tab.

Could someone explain a fix for me please?

Using DELL XPS 15 9560.
Maybe best to mention I use nomodeset in grub to start kali, otherwise it wouldn't start for this model.