As you are saying the app build is taking a long time, what I am understanding is you are doing cloud build using GitHub and appcenter.
What you can do as an alternative is build it locally (https://docs.mendix.com/howto/mobile/native-build-locally). So you can build the app locally and get the files in the build folder that you have configured in Native Builder. Transfer this folder to a Mac machine where you have XCode installed. Install the required packages (npm and pod) as mentioned in the documentation. After this, you can connect an iPhone to the Mac or use Simulators to run and check the app. Since you are running it from Xcode, you can see all the logs from the application also can add logs manually if required.
A local build would be taking less than 5 min and a build process in XCode also will take less than 5 min. So you can make changes and test in 10 mins instead of 30, but here you have to put more manual effort.
This is how we were doing it now. And we are building IPA also locally only after successful testing.
Just one thing as your app is using the camera. Make sure have added the required permissions in App capabilities section in Mendix Native Builder