I was unable to ever get it to fly reliably without GPS. It was probably stupid to drop $7K on drone GPUs and all kind of gadgetry (6 battery bay for rapid charging, etc), but it was just really really hard to pilot around in Maryland (Montgomery County). I would constantly have it throw up warnings and alerts, even only hovering a few feet above the ground for small scale testing. I would have to disable the GPS to do small scale testing, and then with GPS enabled, it would straight up not allow me to pilot it. When I moved to Miami, brought it down there, but I managed to find an apartment right smack-dab in the MIA no-fly zone as well. The smaller drone was allowed to fly though, so I eventually got a small Mini 2 IIRC, which was a lot easier to pilot, but I was just so disappointed in not being able to use the larger scaled up version. I wanted to do realtime facial recognition (not at scale, just to show that commercial drones can be turned into research demonstrators) on the onboard GPU (apparently just a NVDA Jetson from 2017 era)

The irony is the M100 is genuinely great hardware - the payload capacity, the SDK access, the flight time with extra batteries. But DJI's geofencing treats the entire DC metro like a no-go zone, which makes sense from their liability perspective but means the thing is basically a $7K shelf ornament unless you want to deal with LAANC authorizations for every single flight.