在 ios 14+，flutter debug app 只能从工具里启动运行。一旦脱离。点击 app 就会闪退。这个时候，打 release 包就很有必要了。虽然这个包有效期是 7 天，也是好的。当然，有开发者证书更好。
原话
In iOS 14+, debug mode Flutter apps can only be launched from Flutter tooling, IDEs with Flutter plugins
or from Xcode.
Alternatively, build in profile or release modes to enable launching from the home screen.
解决方法
flutter run --release
或
flutter build ios
flutter install