Torte

Did you try loading the "pinctrl-rk805" module?
This was once directly compiled into the kernel and later externalized into a module. And IIRC that happened when switching to 6.12.
If loading that module helps, then adding it to the MODULES line of the board's config like this should fix it.

I wrote a small guide for customizing the status LED's behaviour on the MKS-Klipad50 board.
 
The available LEDs and their names in "/sys/class/leds/" will be different on other boards, but the general behaviour should be the same. Just make sure to change the filenames like "firefly:blue:user" in the examples to those available on your system.