After painfully starting from a bare-bones react-native expo app and adding functionality bit by bit, I found the issue was the stack navigator code. Once I had it narrowed down to that, I found that I missed installing the support packages necessary for stack navigation: npm install react-native-reanimated react-native-gesture-handler react-native-screens react-native-safe-area-context @react-native-community/masked-view And that you have to include: import 'react-native-gesture-handler'; At the top of your App.js file - but in my case, I had two files with stack navigation so it wasn't enough to include that import just in App.js but also in that other file. Once I did this, no more crashes!

Just to update this - it tuns out the ipa file that I generated from the base expo template was fine...the hack I found to unzip it and transfer the app to the simulator doesn't work. Once I "published" that base app to TestFlight it loaded find on my iPhone. So, there is something specifically wrong with my app - what I have no idea. And, I'm not sure how to proceed in troubleshooting other than start with the base app, keep adding code, and keep building/publishing.

Just to update this - it tuns out the ipa file that I generated from the base expo template was fine...the hack I found to unzip it and transfer the app to the simulator doesn't work. Once I "published" that base app to TestFlight it loaded find on my iPhone. So, there is something specifically wrong with my app - what I have no idea. And, I'm not sure how to proceed in troubleshooting other than start with the base app, keep adding code, and keep building/publishing.