I just starting using drone deploy about 3 weeks ago but with the update to the mavic's firmware it's become completely unreliable. They have gone through two versions since then and I don't want to spend any more time on their software.
I had that running yesterday. The maximum return to home height was 150 meters. I am mapping a plot of land that goes from sea level to 1140 feet from a take off point of about 200 ft elevation. If return to home becomes active when I am flying over the higher elevations I think it will crash the drone.
Here is the map from 5 flights:
I tried Drone Deploy and had similar issues. I set it up for a fairly modest trial, covering about 10 hectares. It got a quarter of the way through and went walkabout.