Why do i die 2 sec later after cover or dodging?

A higher ping doesn't mean you are harder to hit because the server doesn't know you are already in that location and think you are still in location X
That could be the reason you die while you are in cover, because the server hasn't received this update yet, but 2 seconds in a long time to be in cover and still dying, that doesn't sound like 85 - 100 ping