The takeoff altitude (service ceiling) specification is quite conservative. For example the Mavic 3 has 6000 meters max service ceiling, but people have taken off from the top of Mt. Everest with it, and ascended to over 9000 meters above sea level.
I really am trying to be kind. It sound like you need something a little more than a flip.. a flip is a good drone but we dont want the little motors over heating or failing. I thinkrwlix le chat will agree. A slight gust unbalanced the drone...
It's the gusts in mountainous terrain that will give you the nasty surprises.
I've flown from the top of some pretty pedestrian mountains (compared to the ones near you) and wind conditions have been dead calm on the way up, but running at a...