Does anyone really know with complete confidence what would happen if a pole shift occurred?
Not that I'm aware of.
But one line of research that is potentially concerning, either directly related or coincidental, is a physical axis, or geographical pole shift.
A planet rotating and wobbeling like a top while floating in space has the potential to tip too far and actually flip over and out of control untill it re-establishes a sound wobble pattern or takes another more drastic course of action, like out of orbit or even its general physical shape and form tearing itself to pieces or shifting the crust and or mantle if the balance between gravity, mass, and centrifugal force should falter.
Something this line of videos touches on and is directly referenced to in the above debunking attempt.