Starting, the cheap way

Hello there.
I have a RPi 4 B+ 2Gb free of use, i’d like to try this project. I have EV200D Googles and looking for some LONG RANGE vibes (Taranis X9 Lite with Crossfire Nano TX), my main Plane and Drone are getting over 30 minutes of flight times.

I’d like to try it on my drone / plane, but the cheap way x)
I’m looking for around 10-20 kilometers of range.
I’m good with electronics, but don’t know which one to choose, is a Pi Zero W enough for the air unit ?

I’m planning to use my EV200D / EV800D / Moneagle as main display to reduce the cost x)
What do you recommend for some OpenHD “long range” & “cheap” build ?

Zero is fine for air…

Screen should be fine. Touch is desireable but otherwise a mouse can be attached to groundpi to manipulate the “app”/osd

For long range antenna choices and elimination of interference are most important. Of course any basic system needs adequate and clean power to the components (power supply is a common issue)