It has been confirmed that the current firmware does not function properly with the newer v4 D1-mini with the USB-C connection:

The v4 board will broadcast the ESP-ParkAsst hotspot, successfully join wifi and the LEDs will show a normal boot sequence. The web settings page will be accessible and can be updated with new settings. But the system will go into sleep mode and will not respond to changes or distance measurements from the sensor.

Until this issue is addressed and a new firmware version released, you must use the D1-Mini v3 with the micro USB connection for the system to function.