Discussing operation of long range transmission for remote control vehicles

TL;DR: Im working on an RC car project and ive been wondering how long range transmission work for RC drones/cars?

Is it based on radio frequency technology, or maybe LASER or optical transmission? What are some common methedoligies? I recently learned about the DJI 03, looks like a pretty sick FPV system. reading up on the documentation to see if i can discern how there communication system works. I have a kit for an RC arduino based car from Elegoo, which uses wifi modules for communication and control between your phone and the arduino, which is what got me started on this journey. The video quality isnt too bad but control latency gets pretty bad behind a wall. Plus I imagine the frequency isnt adequate really for high fidelity transmission requirements.

Id be interested to hear any thoughts and advice on what to research on this topic!