This method lets you continue to build out the app each time without having to mess around. Everything else I tried resulted in the app not being buildable by Unity as assets were missing or doing nothing.
- Set the launch screen options in Unity to None
- Build the app
- In the Xcode project select the Info tab at the top and remove any references to “launch screen”. There’s probably ipad/iphone/ipod lines.
- In Xcode add a custom storyboard to the project
- Assign it to the Xcode project under when you set the app icon
- Build and enjoy