I think the vertical scroll squash can be done with the Flickable boundsMovement property.

[Drew Naylor]

I'll have to have it do FollowBoundsBehavior to make it go outside the thing and overshoot, but otherwise I can just do a transform: Scale and have the X-axis (or maybe it's Y-axis?) of the Flickable shrink according to the current position of how far we are outside the Flickable area. It's the verticalOvershoot value that needs to be used to know how far over the scroll bounds we are. Here's the documentation on boundsMovement, I can probably modify the first example with the transform but may also need to use stuff from the second one:

https://doc.qt.io/qt-6/qml-qtquick-flickable.html#boundsMovement-prop