Also, it is my experience that a very few number of pilots have ever experienced any extended period/s of real/actual extreme turbulence.
I’d second that. The methods described are for when you can’t read the instruments for the shaking and the stall and overspeed warnings are going off at the same time.
Spilling tea mid-Atlantic and wondering if the crew should be sat down or not doesn’t come close.
I have only encountered what I would describe as severe turbulence in a jet transport once in 20+yrs of flying and I do not wish to encounter it again: it was a fight just to keep the brown and blue the right way round, nothing else was controllable.
The effect of V/S zero is probably type dependent - on the ones I’ve flown, if you were displaced from your cruising level they would probably not attempt to return to it, just try to fly level at the new datum...