Another thing I realized lately was that my laptop screen was very dark, not bright at all like my external screen so it was hard to use both. I use Debian Testing LXDE as it is quite light and I dont need anything as heavy as Gnome/KDE. So I struggle how to adjust the brightness but finally got it.

I had to try different programs but finally a blog showed all possibilities and found the one that works for me.

$ brightnessctl set 800 -d intel_backlight

The next thing, I had to be sure that was effective after reboots…. So not sure if this is very clean solution, but I just added that command to my .bashrc. It works. Moving on.