Hello Rasmus Thanks for posting in our Q&A.
We usually use app configuration policies to customize app settings. However, the available configuration parameters and the implementation of the configuration parameters are decided by the developers of the application. We must get these configuration settings (keys and values) from the supplier of the app. https://learn.microsoft.com/en-us/mem/intune/apps/app-configuration-policies-use-ios
For this issue that enable "Camera Uploads" in iOS OneDrive app via intune, it is needed to get the configuration parameters from OneDrive. So, it is suggested to contact OneDrive support to get more help.
Thanks for your understanding.