USB Serial not detected on OSX 10.15.7

I have a MkII Challenger 2040 Wifi/BT board that never appears as a serial device on my Mac. I can upload a compiled build after putting it into BOOTSEL mode that appears to run correctly (a basic blink), but it never appears as a serial port in the Terminal (ls /dev/tty.*), the Arduino IDE or PlatformIO.

The identical USB cable and identical USB port will happily detect an ESP32-S3 Feather, an M4 Feather and an M0 Itsy with no issues. I have also tried in a Macbook anyway and that isn't detected either.