What worked for me on macOS Big Sur 11.5.2 is using the ESP32C3 built-in USB via GPIO18 and GPIO19.
What also worked for me on macOS Big Sur 11.5.2 was downloading and installing this driver CH9102_VCP_SER_MacOS from here. After a reboot and plugging in M5StampC3 via USB this port show up
/dev/cu.wchusbserial...(in addition to
/dev/cu.usbmodem...which did not work).
read here for a possible solution.