Light trigger on state change ? Is there a possibility?

I want to set global variables before my custom I2C takes action:

light:
  - platform: monochromatic
    name: "Kitchen Light 1"
    id: "kl1"
    output: custom_i2c_output 
    on_...: 
    - globals.set:
        id: channel
        value: '0x80'

    on_...
    - globals.set:
        id: channel
        value: '0x80'

This should happen on ON or OFF or Brightness change. .
on_turn_off becomes true only after the light has reached the finally state off. When the race is run without my globals.
I could not find the appropriate trigger. Is there a way to achive this?

Thankyou Christian

There is only a light turn on / off trigger. And this was only added recently: https://esphome.io/components/light/index.html#light-on-turn-on-off-trigger

I thank you for the quick answer! Pity! Maybe I can solve this via MQTT.
Regards Christian