I've got a sweet answer for you.
Same scenario, 2k, turn off engine, pull it up into a loop. (to get to almost 0 airspeed) so the prop stops.
I tried it your way but in level flight about half the time the prop wouldn't stop.
Point nose down, inside 3 seconds the prop is spinning again. All you did was apply airspeed.
That is the way they worked, accept it. The force of the air at 100 mph is enough to turn over the engine.
Now, care to continue digging that hole or have you had enough yet?
Here's what I want you to try.
Take off in a Dr.1 and get it to a reasonable altitude. Press X to engage level flight. Push the E button. After the stall horn start honking really loud, the prop will stop turning. Now... Press the E button again. Now ask yourself if the resulting action is possible in ANY WW1 era aircraft.