Rgbcct to rgbw

Hey

i bought a rgbcct controller for a led stripe but want to use it as a RGBW, I am not able to get it working with customize.

tried for example:

homeassistant:
customize:
light.tube_kueche_licht:
supported_color_modes:
- rgbw
color_mode: rgbw

It changes the interface but doesnt behave light i am expecting it.

What am i doing wrong?