Fix iOS white screen on Expo / React Native app (Android works, iOS blank)

I have an Expo / React Native app (SDK 56) that wraps my website in a mobile app (WebView). The Android version works and is live on Google Play. The iOS version builds and installs fine through TestFlight, but shows a blank white screen on launch. This is already well-diagnosed — I can hand you a detailed write-up so you can skip straight to the fix: A stripped-down minimal app (just one line of text, no WebView, no other libraries) STILL shows white on iOS — so it is not my app code. The device console (read on a Mac) shows the app launches and runs with NO crash and NO error — it's a silent React Native rendering failure on iOS. I already tested toggling the New Architecture on — still white. Same code works perfectly on Android. I need someone to find the real cause AND fix it so the iOS app actually loads on a real iPhone. Deliverable = a working iOS build I can install and open from TestFlight. I have full project access plus my Expo/EAS and Apple Developer accounts set up. Please confirm in your proposal: (1) you've debugged Expo iOS white-screen / native startup issues before, and (2) you have a Mac to run the app in Xcode and read the console.