cordova-plugin-customurlscheme throws the same error that
android:exported needs to be explicitly specified for element <activity#your.bundle.id.MainActivity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
So I think maybe you want to add it to the list of plugins which have been reported to cause problems published on Building for Android 12 | VoltBuilder an add your magic
-android12 flag to it