How to get the real vertical dimension in AIR

HI, everybody. I'm testing an app developed in AIR for Android on the Xiaomi Redmi note 9 I've recently purchased. With Adobe Animate I set my vertically oriented app (480 x 800 px) to fullscreen activating an option in Air for Android settings window, and configuring the tag <application android:hardwareAccelerated="true"> <meta-data android:name="android.max_aspect" android:value="3.0" /></application> into the XML file. Up to there, no problems.

Indeed, my issue is a matter of dimensions: actually, the app is higher than 800 pixels. In other words, it features two rectangular areas, "added" both above and below the central screen.
I want my app to be responsive, but I cannot use the additional space, because I do not obtain the real vertical dimension.
Capabilities.screenResolutionX and Capabilities.screenResolutionY properties return 1080 and 2400, that is to say the same nominal resolution values provided by the device vendor.
However, managing with AS3 to dinamically arrange a movieclip, I've found out that the effective display resolution is 480 x 1024.

How could I use AS3 to obtain directly this 1024 value, that is the vertical space actually occupied by my app? It would help me during the app deployment.
Thanks in advance.