Jetson Xavier NX connection with ground without internet for live processed video transmission (Distance 5 or 6km) mean the altitude of the UAV from the ground

Maybe can Camera to Jetson Xiaver NX, process video, then Ethernet Jack out, convert HDMI to H16 Pro HDMI in, stream down. another example.

H16 Pro Airunit seems to have a LAN RJ45 input port. then, Camera to Jetson Xiaver NX, process video, then Ethernet Jack out to H16 Pro RJ45 input port (need further read their capability in their manual).

Alternatively, Pixhawk Jetson Baseboard Bundle.

You may be interested to read this up.