PCB Requirements:
- 4x 12V PWM Transistors
- 1/2 ARGB Pins + 5V supply
- ESP8266 SMD traces
- 12V-5V Buck converter
Sketch is neither correct nor conventional, it's just to show the general layout and routing beforehand. The left half could be supplied with its own 5V supply, and then the right half with the buck converter, transistors and all 12V shenanigans could be broken off for a very tiny ARGB controller
Kicad ESP footprints used: https://github.com/jdunmire/kicad-ESP8266