If you are recording a native App and your recordings have large blacked content, or the entire recording is mostly black, it's generally due to the security PII (Personally Identifiable Information) flag set in your App.
The best solution is to disable the flag for testing purposes:
https://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_SECUR
...or if you cannot do that, build a prototype in any prototyping tool and use that to test the flows you want to test.
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