I2S microphones on ESP32- how high can it go?

I know it's been a long while since anything got posted - way too long! However, I've been playing a bit with the ESP32 using an I2S digital microphone, and that got me thinking - just how high a frequency can such a microphone actually pick up? To answer that question, I felt I needed to do some digging into how we go from the microphone to a digital signal. I also delved into overclocking a microphone!