You could connect white LEDs to farbwerk with some soldering and/or clever wiring...
Why don't you adjust RGB outputs to make it white?
If your LED is too purple when R=100% G=100% B=100% then you could decrease R and/or B channel and get more accurate color.
You are absolutely right! Before I tried removing a little blue and it looked the same. After your advice I removed quite a lot of blue from the light and now it's quite amazing.
I used those settings if anyone is interested.:
R 33
G 30
B 10