Are there any commands to control the keyboard backlight brightness and color and to turn the light on and off?
I have a System 76 Darter Pro, and the fn key combinations to control the brightness and color are not working. I put in a ticket with System 76 but they had no answer. My keyboard lights are on full brightness and bright white. I would like to turn them off to save battery power or at least use a different color and brightness. I put Parrot OS and Mint os in on USB keys and they do not light up the keyboard.
sudo xmodmap -e 'add mod3 = Scroll_Lock'
sudo xset led 3
the scroll_lock key should turn keyb on/off
It didn't work. I had a ticket in with System 76 and they have no answers. Searching the Internet pretty well convinced me backlit keyboards are just a problem.
I had been having a lot of freezes and crashes on this laptop lately after the last few upgrades too. I put Mint on this laptop for now and will try Ubuntu Mate again when the next LTS version comes out. I also have it on a Dell Inspiration where it is working fine, so I am not going away. I prefer Ubuntu Mate aesthetically. There are other minor differences that I find Ubuntu Mate better than Mint Mate. Not my ideal solution but it will work for now
If you feel it something you can do, you can install the original POP! OS and then install the Mate desktop shell. I have only done something like that twice and it was an OK experience. I didn’t spend much time with it but it worked. I did it with Rasperry installing the Xfce desktop environment and on a laptop installing Mate over Xfce environment. You will not get Ubuntu’s Mate experience which is tweaked already, but you will get a vanilla Mate experience but maybe with the features you need. Did you try the 20.04 LTS for Mate? That’s the same base that Linux Mint is using so maybe it has something to do with the kernel. Good luck getting it to work. Cheers…. 
I don't think I have the skill level for that. I can see a multitude of other problems with default apps too. Thanks for the suggestion.