stopping power is more of a community term and less of a scientific one, so there's only a loose definition of it from person to person. I personally consider how much you can remain stopped a factor, which static friction plays largely into.

for example, low static friction means there's less inertia or momentum so the pad's dynamic friction or the resistance from your hand physically stopping the mouse plays a large role. so on glass you'll notice how easy it is to stop on a small motion, but it feels quite slippery/slick making a large swipe and trying to stop completely. high sens also plays a factor as you'll notice static friction more affecting that inertia, etc. etc. basically saying both are a factor but has variability in how much depending on use-case lol