My keyboard backlight works on the Lock Screen but it disappears when I log in

So I have a problem as the title says my keyboard backlight works on the lock screen but then doesn't work anymore after I press enter after typing my password. I tried installing Karabiner but it didn't work so I don't know what to do now? Btw I use macOS Sonoma. Even in the settings there is no option to adjust the brightness or to change the light sensor. I tried being in the darkest room possible bot the keyboard backlight refuses to work and I tried f6 and fn+f6. Thank you for the response. I almost forgotten it is an MacBook from 2019 it os an a1932