After discovering two things, this project suddenly fell into place: the ESP32 had libraries for it to act as an Apple HomeKit accessory and LEDEngin make awesome 7-colour LEDs! (that’s Red, Green, Blue, Amber, Cyan, Violet and White LED dies all in one package!)
After spinning a little board with 7 LED buck constant current sources and an ESP32, this provides much satisfaction by being able to control it from my phone. It even reports the heatsink temperature back through the HomeKit interface.
Fred Temperton 