sorry I have not read all the recent posts but yeah an active/passive switch would work if it’s a DPDT. it’s exactly the same switching circuit than in a “true bypass” pedal. all the push/pull pots I’ve had were DPDT.
the base logic is pretty straightforward :
and the best way to wire this on a DPDT is this one, because it allows the preamp to be grounded when not in use :
'hope it helps !