Some of the MCU's have multiple SPI and I2C buses. An ESP32 has 2 user accessible SPI buses and 2 I2C buses. One I2C bus can be the master that does the thing with the display and the other I2C bus can do the slave thing.
Some of the MCU's have multiple SPI and I2C buses. An ESP32 has 2 user accessible SPI buses and 2 I2C buses. One I2C bus can be the master that does the thing with the display and the other I2C bus can do the slave thing.