Descent speed limit when flying to an altitude lower than the takeoff point

I did an autopilot from the top of the mountain to the footof the mountain.
In this case, the flight to an altitude lower than the takeoff point.
The descent speed at this time was limited to about 0.8m/s. I would have preferred a much faster descent speed but it would require a big time so slow. Is there a workaround for this?