problem with the quality and colour camera of my smartphone

I use my vuforia and unity (up to date) to make AR applications on my phone.

However I have some problems: The applications normally work one out of 5 times on my phone ( XIAOMI MI NOTE 10 Android 10), while on my girlfriend's phone ( HUAWEI P20 Android 9) the applications work all the time.

The rest of the time I have the following problems: -the focus is not done automatically (problem solved with one line of code). -camera quality is very low -the colours are not the right ones (e.g. red becomes blue, purple becomes green etc.).

I have done a lot of research to solve the problems but nothing works.

I really need help.

Thanks to you :)

Translated with www.DeepL.com/Translator (free version)