CORRECTION: The code I was able to get working was from https://github.com/aat440hz/RF433-SignalTest-M5StickCPlus2/blob/main/RF433-SignalTest-M5StickCPlus2.ino , which displays the signal on the M5Stick.
I've since tried using the example from the M5Stack repo ( https://github.com/m5stack/M5Stack/blob/master/examples/Unit/RF433/RF433.ino ) have flashed the images to M5Core devices (one with '#define RF433RX' and one without, as per the instructions) but pressing the buttons doesn't do anything, and I'm not seeing anything displayed on serial for either device either.
I know both units work because I can flash firmware on other M5Stack modules (like the M5StickCPlus2) and send and receive RF.
Does the example on GitHub just not work?
Short video showing sending unit doing nothing with button presses: https://imgur.com/a/mcsAZFT