Hello. You can try to use 'Sync for DJI' app. This app allows download even 4K video on iPhone even in the background without losing any data and quality. I found this app for iOS Sync for DJI on the App Store .
After a flight, I open this app, it automatically connects to my drone. I select images and video and tap on download or share button. The app works with Wi-Fi and connected RC. Also, I use it for my OSMO + too.