1. RPi Zero 2W + 64GB SanDisk High Endurance
2. Cheapest SDR (aliexpress) and PCB antenna (aliexpress) https://www.adsb.lol/docs/hardware/adsb-equipment/ - a 90° SMA female-female or straight depending on how you position the antenna/SDR.
3. https://adsb.im image
4. ???
5. Profit!!

I’m using a ADSB exchange usb dongle I bought on Amazon with an upgraded antenna. It had a filter built in and I typically get about 200 miles of range.

I don’t feed data to adsb exchange though.