default or selected kernelversion does not have config value CONFIG_BACKLIGHT_CLASS_DEVICE.
Result is shown for kernelversion 5.9.9

Lowlevel Backlight controls

modulename: backlight.ko

Linux Kernel Configuration
└─> Device Drivers
└─> Graphics support
└─> Backlight & LCD device support
└─> Lowlevel Backlight controls

This framework adds support for low-level control of the LCD
backlight. This includes support for brightness and power.

To have support for your specific LCD panel you will have to
select the proper drivers which depend on this option.

source code: