@Kaxu From C++ side you can use QQmlComponent. After creation cast it to QQuickItem and then set x and y coordinates using setProperty. Follow the example on that link. Then after creating
QObject *myObject = component.create();
QQuickItem *item = qobject_cast<QQuickItem*>(myObject);
item.setProperty("x",x); //x and y which you already have.
item.setProperty("y",y);