Got support from the upstream project. Installing qml-module-qtquick-controls2 qtdeclarative5-private-dev solved the problem:
apt install qml-module-qtquick-controls2 qtdeclarative5-private-dev I looks the missing package qml-module-qtquick-controls2 was the problem. Should qml-module-qtquick-controls2 be added as dependency? Thanks to the upstream project!