Servers by jDrones

https://www.aliexpress.com/item/33060902547.html

CUAV NEW Telemetry 4G LTE-LINK SE Data and Video Transmission for RC FPV Drone Parts whole sale

How does the communication happens between the two LTE devices?
Only through Cuav Cloud Access or I can use custom tunnel, like my own VPN?

Servers by jDrones