It should be possible to adapt the height of the StackLayout to its children's

/**
 * Custom implementation of a simplified StackLayout.
 * Its height adapts to the height of its current child.
 */
import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3

ColumnLayout {
    property int count: children.length
    property int currentIndex: 0

    onCurrentIndexChanged: {
        hideAllButCurrent();
    }
    Component.onCompleted: {
        hideAllButCurrent();
    }

    function hideAllButCurrent() {
        for (var i = 0; i < count; ++ i) {
            var child = children[i];
            if (i == currentIndex) {
                child.visible = true;
                child.enabled = true;
            } else {
                child.visible = false;
                child.enabled = false;
            }
        }
    }
}