I have scaled this plunger down to 10cm (most Australian toilets bowls are smaller than U.S ones) and added a handle with a cap to either hang it up or just hide the screw hole.

If you want a really long handle you can print 2 handles and they will screw together.

Plunger main needs to be printed with TPU (or other flexible filament) 15% infill

Handle and cap I printed with PLA+