Hello everyone, very late I know but I didn’t come across this lovely board until very recently.
I was thinking of one simple design that could be customized to serve in different situations.
Its a U-shaped sheet (maybe 1/8 inch thick) that rotates around a cylindrical handle and secured to it at different possible angles.
In the pull case, the thin edges are facing the user making it both mentally and physically uncomfortable to push.
When adjusted into the push mode, the smooth rounded end is facing the user but there’s no enough room to grasp the handle making it impossibly hard to pull.
And in case the door works both ways, it can be fixed at 90 degrees possible to pull or push.