With a I2C level shifter, you have a 5V I2C bus and a 3.3V I2C.
You can connect 5V I2C devices to the 5V I2C bus.
You can connect 3.3V I2C devices to the 3.3V I2C bus.
Keep in mind that when an Arduino or a sensor pulls the SDA low, it has to pull both the 5V and 3.3V of the SDA low with all the pullup resistors on both sides.
Maybe I wrote this before, but I prefer the small modules with voltage regulator since the Pro Micro board has no 3.3V: https://www.aliexpress.com/item/Free-Shipping-5pcs-lot-5V-3V-IIC-UART-SPI-Four-Channel-Level-Converter-Module-for/1759225984.html.