registerNatives failed when linking Qt Librarys to Android Project

[morsch]

I have a basic Library written in Qt, that worked fine when importing the .so to android with the libQt5Core.so.
I wanted to add Bluetooth Functionality (-> Qt5AndroidExtras and Qt5Bluetooth lib neccessary) but now i run into errors when loading the library in my Android Project. Depending on the order of loading either

A/Qt: Can't find "org/qtproject/qt5/android/extras/QtNative" class

or

A/QtBluetooth: Can't find class "org/qtproject/qt5/android/bluetooth/QtBluetoothBroadcastReceiver"

both with registerNatives failed and a java.lang.ClassNotFoundException afterwards.
How can i solve this issue?