I think that you talk about accumlator lag when you say you need a pivot to get it. The lag pressure in the hands will be loaded by the change of direction from backswing to downswing.
There is certainly a blend and overlap of the three Lags.
Accumulator Lag is power package and all of its decisions as to load and release. Pivot Lag is the gear train- the Swinger’s gyro or the Hitter’s Platform that begins from the lower body on up.
Clubhead Lag is the lead and drag of the clubhead, the deliberate, positive and heavy Clubhead/Hands relationship.
The shoulders are part of the pivot (Z1) and power package (Z2), both commanded by the Hands (Z3).