Why is my white balance off? Nikon Z6

[rflophoto]

Hello, 

I hope someone can help solve this issue because it drives me MAD. My white balance is always off! It seems I cannot get my white balance right. The following images were photographed with a Speedlight. However, this also happens with natural light. I shoot with a Nikon Z6. I crank up the saturation in Lightroom to check where the blues, magentas, and purples are. See the attached images.  

[D Fosse]

Your white balance isn't off.

There is very obvious mixed lighting here:

Also, don't forget that colored surfaces reflect a lot of light! That's why studios are always painted in neutral colors, and most photographers (myself included) will wear neutral clothing when doing delicate and color-critical work.