From DJI with a nice diagram explaining how it works:
https://enterprise-insights.dji.com/blog/introducing-4g-connection-for-drones-with-dji-cellular-dongle
Just found this on the support website from DJI:
"The enhanced transmission requires a relay server to facilitate low-latency 4G video transmission coupled forwarding, the subscription fee covers the cost of renting servers and cloud services."...
Impossible.
While both Google Earth Pro and DJI waypoints use a file with the KMZ extension, they are different file types.
A Google Earth Pro KMZ file is simply a compressed KML file. The KML file contains data using the Keyhole Markup...
not to heat up the discussion if DJI will sent flight data to China - but is my understanding correct that in case of a connection lost (normal RC connection), all of your flight telemetry will be sent from the Air 3 via mobile network to DJI...