Hello,
Ive done a quick project on a Teensy 4.0 with two BMP280 sensors, connected via I2C (SCL0, SDA0 and SCL1, SDA1).
Actually I did not get how to proper initialize the second bus to get valid data from the second sensor because both sensor have the same address (0x76).

ArduinoIDE (1.8.13)
Libraries: <Wire.h>, "cactus_io_BME280_I2C.h", <Servo.h>

Attached please find my code:

Code:
#include <Wire.h>
#include "cactus_io_BME280_I2C.h"
#include <Servo.h>


#define RelayHPin 4                // Relay Pin D4
#define RelayTPin 5                // Relay Pin D5
#define ServoPin 9                 // Servo PWM out D9

int relayH = 4;                      // Relay on Pin D4
int relayT = 5;                      // Relay on Pin D5
int analogPin = A0;                // potentiometer wiper (middle terminal) connected to analog pin 0
                                         // outside leads to ground and +5V
int val = 0;                          // variable to store the value read

Servo mainServo;
int position = 0;
int previousPosition;

// Create BME280 object
BME280_I2C bme1(0x76);       // I2C using address 0x76 // connected to I2C SCL0 Pin 19, SDA0 Pin 18

void setup() {
  
  mainServo.attach(ServoPin);
  pinMode(relayH, OUTPUT);         // Pin for relay module set as OUTPUT
  pinMode(relayT, OUTPUT);         // Pin for relay module set as OUTPUT
  
  Serial.begin(9600);

  Serial.println("Bosch BME280 Pressure - Humidity - Temp Sensor | cactus.io");

  if (!bme1.begin()) {
  Serial.println("Could not find a valid BME280 sensor, check wiring!");
  while (1);
  }

  bme1.setTempCal(-1);// Temp was reading high so subtract 1 degree

  Serial.println("tHumdity\t\tTemp");
 
}

void loop() {

  // ***************** Potentiometer reading *****************
  // val = analogRead(analogPin);  // read the input pin
  int setpoint = map(analogRead(analogPin), 0, 1024, 0, 50); // mapping from 0-1024 to 0-50

// ****************** BMP280 sensor reading ********************
  bme1.readSensor();

  // ******************* Humidity and Temp values + Offset ****************
    float h1Offset = bme1.getHumidity() + 0.0;     // Humidity Sensor1
    float t1Offset = bme1.getTemperature_C() + 0.0;     // Temperature Sensor1
    
  // ******************* Humidity scale to servo *************

  // This maps humidity to degrees open for the flap + Operator setpoint
   int position = map(h1Offset - setpoint, 30, 100, 60, 20); // mapping flap min - max incl. Poti offset /act 30, 100, 101, 40
   if(previousPosition != position){
     mainServo.write(position); 
  }
    previousPosition = position;

  // Relay ON/OFF by Servo position
   if (position < 55){                 // Relay OFF if Servoposition < setpoint
     digitalWrite(relayH, LOW);         // Relay OFF 
   }    
   else if (position > 65){            // Relay ON if Servoposition > setpoint
     digitalWrite(relayH, HIGH);        // Relay ON
   }
   
  // Relay ON/OFF by Temperature
   if (t1Offset < 27){                   // Relay ON if Temperature bigger
     digitalWrite(relayT, HIGH);         // Relay ON 
   }
   else if (t1Offset > 28){              // Relay OFF if Temperature smaler
     digitalWrite(relayT, LOW);        // Relay OFF
   }


  Serial.print(F("HumSens1: ")); Serial.print(bme1.getHumidity()); Serial.print(" %\t");
  Serial.print(F("TempSens1: ")); Serial.print(bme1.getTemperature_C()); Serial.print(" C\t");
  Serial.print(F("HumSens1Offset: ")); Serial.print(h1Offset); Serial.print(" %\t");
  Serial.print(F("TempSens1Offset: "));Serial.print(t1Offset); Serial.print(" C\t");
  Serial.print(F("ServoPos: ")); Serial.print(position); Serial.print(" \t");
  Serial.print(F("PotiPos: ")); Serial.print(setpoint); Serial.println(" \t");

// Add a 2 second delay.
delay(100); //just here to slow down the output.
}