Use a 3.3V Arduino board or use level shifters for the sensor and the display.
The OLED display disturbs the I2C bus. Can you try other pins and software I2C (I think the U8g2 has that option). Then you need two level shifters. One for the sensor and one for the display.
If that is working, you can try to connect the OLED display to the real I2C bus (using the same level shifter as the sensor), and see if it still disturbs the I2C bus.