How can I set white balance manually - when shooting

Hey, I am wondering how to manually set white balance on my iPhone 11 Pro (while shooting!) I’m a film photographer among many things and I would find it very useful to be able to use my phone as a preveiw of how the light will look (especially during situations where I shoot under artificial lighting).

As far as I understand, there is no manual white balance control on ANY of the iphone models stock apps - strange to lack such a basic feature that was built in even on the oldest digital cameras. It is useless for me to be able to adjust wb using the photos tint/hue feature. What I need is to override the auto wb and set it at a fixed value based on the film stock I am using, for example 5500k, and then see what the scene looks like on the live preview. Only then can I tell if I need to apply filters to compensate or do I need a different film. I need to see the K value. Are there any apps that you use for this?

Honestly I was pretty dissapoionted at how the iPhone camera handles white balance. We have a range of different iPhones in our family and it seems like all the iphone models just do it their own way, some are yellower, some more blue with no real user control. Not what you would expect, especially on models marketed as “pro”.

Many thanks for your feedback and tips!

Tom