A position on a wheel event doesn't make sense especially with trackpads. So it's being removed.
Unfortunately as kwin is faking windows at fake positions this isn't trivial.
I think we'll have to cache position from the mouse moves? Or map from global?
https://invent.kde.org/plasma/kdecoration/-/commit/4091b18bfef5e1ff8f2924ad18917ebbb14987b0 changes the deprecated posF() to position().
From the QWheelEvent docs:
The functions position() and globalPosition() return the mouse cursor's location at the time of the event.
KDecoration checks whether this position is any of the buttons and if yes forwards the even to the button.
This usage makes perfect sense to me, so I don't think there's anything to do here