Hi guys, I need help, please!!!

I am trying to use this m5 GNSS module with a standard Espressif ESP32-S3-DevKitC-1 development board, NOT an M5Stack Core unit.

I have been successful with part of the module, but I am completely unable to get any data from the NEO-M9N GPS over the UART interface.

Here is a summary of my project and the troubleshooting steps I have taken over many days with no luck:

What Works Correctly:

The module is powered correctly via the 3V pin and GND pins on the M-BUS header.
The I2C communication is working perfectly. I have run an I2C scanner, and it successfully finds the BMI270 at address 0x69 and the BMP280 at address 0x76, exactly as expected.

The Problem - No GPS Data:

I am unable to receive any UART data from the NEO-M9N GPS. I have written test code for my ESP32 that cycles through all standard baud rates (9600, 38400, 115200, etc.) and listens for any incoming data, but no valid NMEA sentences (or any data at all) are ever detected.

My Current Setup and Troubleshooting Steps:

I am attempting to use the DIP switch and the M-BUS header to make the UART connection, as described in your documentation for use with M5Stack Cores.
My current DIP switch setting is:
SW1 (Module RX): Pin #1 is ON, all others are OFF.
SW2 (Module TX): Pin #1 is ON, all others are OFF.
SW3 (PPS): All pins are OFF.

I have tried connecting the corresponding M-BUS pins (based on the pinout diagrams for various Cores) to several different hardware UART pins on my ESP32-S3.

I have verified with a multimeter that the pins have voltage, but no data seems to be transmitted.

My Questions:

can gps data be obtained without a Core Module?

Is there any other initialization step, required pin state, or consideration needed to enable the GPS UART output when not using an M5Stack Core host?

I have tried many combinations and reviewed the schematic and documentation, but I am now stuck. Any detailed help would be greatly appreciated.

many thanks
Alex