JF, I totally agree that the action for getting out of a conventional PIO is to let go of the controls. I differentiae between conventional and other PIOs in that I have no experiences of non conventional pilot in the loop problems either with powered, body shift, or electronically interfaced, control systems, but I suspect that there will be some new feature yet to be discovered.
Clamping controls is fraught with problems as you state; my non-powered controls civil aircraft had an interesting control system - fuselage structure coupling via the pilot’s upper body and ‘stiff’ arms. Gripping the column lower down was attempted on one test; at least until the hand wheel struck the pilot in the face!