Quick update for additional context: The login screen (first screen after splash) imports: google_sign_in: ^6.2.1 sign_in_with_apple: ^6.1.2 The Apple Sign In button is only shown on iOS: if (defaultTargetPlatform == TargetPlatform.iOS) { ... } I noticed that even with a MINIMAL main.dart (no imports beyond Firebase and a simple Scaffold), the black screen still occurs. This suggests the issue is NOT in my Dart code, but in the iOS native plugin registration phase. The flutter_secure_storage plugin was already removed. Could there be an issue with one of these auth plugins (google_sign_in_ios or sign_in_with_apple) registering during AppDelegate initialization that silently terminates the app on iOS 26?

UPDATE: I just realized something. My app uses both: google_sign_in (Google Sign-In on first screen) sign_in_with_apple (Apple Sign-In on first screen) These are the very first widgets the user sees. Could there be an issue with how iOS handles these authentication providers when the entitlements match the provisioning profile? Specifically with the com.apple.developer.applesignin capability?