App is not using GPU for graphical rendering at all

The native Apps and the OS seems to use the GPU quite often for smooth rendering of the GUI interface,The Android App , which uses Qt seems to not use the GPU at all for the Apps content written in Qt. In fact, when it comes to use Qml controls like for example a simple input filed, I can see, that the GPU is involved; strange here is, that the GPU footrpint, made visible by a red rectangle on the screen by the GPU debugging of Android, doesn't disappear any more after the used input filed is destroyed.

My idea is to use the GPU to speed up graphical rendering for creation/distruction of qml objects or also for the whole rendering engine inside the Qt Application content. Is there any way to enable this, or may be there some parameters or options I can go for to make some experiences?

In my Manifest. xml the hardware acceleration tag is already set to true
<application android:hardwareAccelerated="true" ....>