Reproduction steps:
1. Extract "NewXCode.zip (60.9 KB)" and open the folder
2. Open and build for iOS the project in "UnityProject.zip (247.1 KB)"
3. Create a new Xcode Workspace
4. Import NewXCode.xcodeproj (the root of NewXCode you extracted) to the Xcode Workspace
5. Import Unity-iPhone.xcodeproj of the project you built to the Xcode Workspace

All Remaining steps are done in Xcode Workspace

6. Under Unity-iPhone select "Data" and check Target Membership "UnityFramework"
7. Under Unity-iPhone select Libraries -> Plugins -> iOS -> NativeCallProxy.h
8. Set UnityFramework Target Membership visibility to Public
9. Deploy NewXCode target to iOS

Expected result: the project launches successfully
Actual result: project starts launching but the screen stays white/black indefinitely

10. This can be resolved by replacing "<root of the Project from step 2>/Classes/UnityAppController.mm" with the one attached in edits

Reproducible with: 2019.4.10f1, 2020.1.5f1, 2020.2.0b2

Devices tested:
Reproducible with:
iPad Pro 12.9 1st gen (iOS 13.4.1)
iPhone XR (iOS 13.4.1)
iPad 9.7 6th gen (iOS 14.0b7)
Not Reproducible with:
Could not test with:
iPhone 5C (iOS 10.3.3) OS ver too low
iPad Air 2 (iOS 11.0.3) OS ver too low
iPhone 8+ (iOS 12.0) OS ver too low

Notes:
1. A video of me reproducing the issue from step 1 is attached
2. Steps 6-8: not possible to do in 2018.4, the project will deploy without errors though