• Download the zip file from the Example Demo link.
• Open bmm150_Arduino.ino under Arduino > bmm150_Arduino
• Search Wire.begin() in the code (you can find one in the line 149)
• Change it to Wire.begin(0, 26)
  This is necessary if you are using a Hat version of ENV II HAT, which is connected to the GPIO pin side of the M5Stick variants. If you are using ENV II Hat connected the Grove port, you don't need to change it.

After this modification, the code should work.

I adapted what is below from the M5Stack examples for StickC (non-Plus) and ENVII hat to work on an Atom. The only real changes I made were to write out to serial instead of LCD and use the LEDs of the Atom, so it might help you fault find. NB Library and pins need changed to suit your StickC Plus. It's a bit rough and ready, but it certainly worked on ENVII with Atom and StickC.

#include <M5Atom.h> // Swap out for StickC library
#include "M5_ENV.h"
#include <Adafruit_BMP280.h>
#include "Adafruit_Sensor.h"

SHT3X sht30; // SHT3X sht30;
Adafruit_BMP280 bme; // Adafruit_BMP280 bme;

float tmp      = 0.0;
float hum      = 0.0;
float pressure = 0.0;

void setup() {
    M5.begin(true, false, true);             // Init M5Atom
    delay(1500);
    // M5.Lcd.setRotation(3);  // Rotate the screen.
    // M5.dis.fillpix(0xFF0000); //LEDs of atom to black
    Wire.end();
    Wire.begin(19, 22); // Swap out for StickC 0, 26
    sht30.init();
    Serial.println(F("ENVII Unit(SHT30 and BMP280) test...\n"));
}

void loop() {

    while (!bme.begin(0x76)) {  // Init the sensor of bme
        Serial.println("Could not find a valid BMP280 sensor, check wiring!");
    }
    // M5.dis.fillpix(0x00FF00); // Turns atom leds green
    pressure = bme.readPressure();  // Stores the pressure gained by BMP.

    sht30.get();           // Obtain the data of shT30.
    tmp = sht30.cTemp;     // Store the temperature obtained from shT30
    hum = sht30.humidity;  // Store the humidity obtained from the SHT30
    // M5.Lcd.setCursor(0, 20);
    // M5.Lcd.fillRect(0, 20, 100, 60,
                  //  BLACK);  // Fill the screen with black (to clear the screen).
    Serial.printf("Temp: %2.1f  \r\nHumi: %2.0f%%  \r\nPressure:%2.0fPa\r\n",
                  tmp, hum, pressure);
    delay(2000);
}

When I checked I2C addresses with I2C_Tester example, With Wire.begin(), it listed only three internal devices. With Wire.begin(0, 26), it listed three additional devices in ENV III Hat including BMM150 at 0x10.

Btw, sht3x has Wire.begin() in its constructer. So, it's better not to have the sht3x instance if not necessary. It could lead to confusing results.

#include "bmm150.h"
#include "bmm150_defs.h"
SHT3X sht3x;
BMM150 bmm = BMM150();
bmm150_mag_data value_offset;
Adafruit_BMP280 bme;

With the StickCPlus include you should not need to add Wire.begin(0, 26);

Also I don't understand the three

Wire.beginTransmission(BMM150_I2C_Address);

-Terry