Fran you might as well stop mentioning pronating. You don't understand what a pronated grip is and every time you mention it you mischaracterize it lol.
A pronated grip is one where the hand goes on to the cue in a pronated position. It stays stable in that position. The idea of pronating actively at impact is absurd and not at all what anyone advocating for a pronated grip ever suggests. The entire idea is that the pronated position increases stability and keeps the conditions of the wrist/hand pretty much feeling stable and unchanging. Most people use the term interchangeably with 'thumb-down'...which is inaccurate but the thumb pointing down is a feature of this hand position. Pronating (and remaining pronated) is one of the ways players stabilize and lock in a thumb-down orientation of the hand.
Honestly, for all that you've said about the grip it wouldn't surprise me if yours was actually pronated lol. This position fits like a glove with a back 3 finger grip (tho it works with any fingers, even those 'twisting' front fingers you rail about....the pronation prevents the twisting.). There is excellent stability through the wrist/hand, making it unchanging through delivery. And yes, there is absolutely no pronating at impact lol...that would be pointless and counterproductive and nobody who ever suggests a pronated grip ever had that in mind...this was only mentioned by you, and as I said, is a complete misrepresentation of what a pronated grip is.