I've been trying* (sorry for the typo)

That's because Alienware has two graphics card (Nvidia and Intel) and the Nvidia card is primarily used. So basically the Intel card is a passenger and in this case Windows OS is able to control the brightness but Linux cannot because of the Nvidia graphics card situation plus there's a bunch of stuff about nvidia and linux you will find online and some of them aren't pretty and you will most likely have to find ways to get products from Nividia to operate with linux and these include downloading drivers or just plain simple jumping through hoops just to get things to run smoothly. I mean you could do a bunch of research on how to get "things" working but you most likely just want to rip out you hair but your most best off just running kali linux on probably any other laptop/desktop without nvidia in the mix but remember there will most likely be a "Linux Solution" to problems and you never know you might find a way.

If everything works and you're able to do penetration testing and hacking and your only problem is the brightness then you can either deal with it or some how find a way to fix it or use Kali on a different laptop/desktop.

just remember when picking out a Stable Distribution for your needs, you gotta keep in mind of hardware and in this case Intel is good.

Thanks for the reply... I had a previous version of KaliLinux with this exact same Alienware and Xcalib worked. However, when I upgraded the to the latest version of Kali, things went south. So, I was wondering if maybe there was an existing solution. Anyway, I'll roll back to that Kali version and finally I'll be able to work without burning my eyes. Also, have you tried KaliLinux on Amazon WorkSpaces? I couldn't find any image. Thx! Sophie

You tried editing /sys/class/backlight/nv_backlight/brightness ?

also what do you mean by "installing drivers" -- you installed the nvidia proprietary drivers?

This report has been filed against an old version of Kali. We will be closing this ticket due to inactivity.
Please could you see if you are able to replicate this issue with the latest version of Kali Linux (https://www.kali.org/get-kali/)?
If you are still facing the same problem, feel free to re-open the ticket. If you choose to do this, could you provide more information to the issue you are facing, and also give information about your setup?
For more information, please read: https://kali.training/topic/filing-a-good-bug-report/