I've just set up the keyboard led control on a new Clevo NL55PU laptop with Linux Mint 21.3 Edge installed. To do this it is necessary to temporarily disable UEFI Secure Boot before running the instructions for the new version and rebooting. If required, UEFI Secure Boot can be re-enabled later.
Using the Fn key and the /, *, +, or - numeric keypad keys will give the following:
Fn and / steps through the led colours available
Fn and * turns the keyboard leds on or off
Fn and + increases the led brightness
Fn and - decreases the led brightness
NovaCustom has been very helpful in supplying this fix, and helping me getting it to work.
Jeff