Anecdotal evidence doesn’t help you. Observations can find a trend, which can be further studied. The disease is complex, there are likely multiple factors. Think of cancer, some people smoked for decades and never got it, others died young. Doesn’t mean smoking doesn’t cause lung cancer

Inuit people actually had significantly lower heart disease than the rest of the world until recently. Smoking increased in the population along with lifestyle changes.

Eh, I feel like this is a bit misleading. Cortisol is bad for your heart. Unusually high or low temperatures causing stress makes sense. As far as I know people living in the extremes on our planet don’t have worse hearts.