Hi @BIZDIK, and welcome!
Yeah, the keyboard backlight is one of those essential nice-to-haves. Don’t really need it, until it’s gone.
Searching the AUR, I find many packages for exactly that:
$ pamac search msi
[...]
msi-perkeyrgb 2.1-2 AUR
Configuration tool for SteelSeries per-key RGB keyboards on MSI laptops
msi-keyboard-light-manager 1.0.0-2 AUR
MSI keyboard light manager
msi-keyboard-light 0.1.0-3 AUR
Tool for msi keyboard backlight administration
msi-keyboard-git r19.fb57be9-2 AUR
Utility to control MSI Steelseries keyboards, written in C++
msi-kb-backlit 0.1.0.1-1 AUR
A command line tool to change backlit colors of your MSI keyboard
[...]
So perhaps try one of those. Install it with:
pamac build <packageName>
Where <packageName> is the name chosen from above you’d like to install.
Hope this helps!
If it doesn’t report back with more information: