Try browsing to /Library/Logs/yourgamename
UE Crash logs may be at /Library/Application Support/Epic/Unreal Engine/4.27/Saved/Crashes
Editor logs can be found at /Library/Logs/Unreal Engine/yourgamenameEditor
Look around in those areas for logs that match the times you made the attempt. To be honest, it’s been hard to keep track of how they organize the logs, so it can take some hunting around the Library. I’ve not launched to IOS so the paths may be more complex.
Edit: Since people are still viewing this thread…
Correcting paths per @ViceVersa response. All /Library… above should be ~username/Library.
On the comment concerning hidden files, search “How to show hidden files in macos” and find the method for the latest version of macos. It has changed since the early days of macos.