No way to sync up two properties after the binding between them

Unfortunately, it is not possible to achieve the old "QSlider/QSpinBox value sync up way". You recall, we connected the signals to the relevant slots, and the value of those were always in sync.

I have tried to achieve it more times in qml codes, but I finally got the sake to report the issue. Hence, something like is going the end up "Binding loop" for no real reasons as far as I see:

A: B;
onValueChanged: {
B = A;
}

Sadly, it is a very abstract issue, and I do not currently even know a workaround for this in my QML application. :/