What is the sampling rate of gyroscope for Pi4 yellow cube?

Hello, this is Jimit. I have a few questions: What is the sampling rate of the gyroscope used in the control rate controller of the Pix4 Yellow Cube? Additionally, what is the sampling rate of the IMU (Inertial Measurement Unit) for EKF (Extended Kalman Filter) state estimation? Lastly, could you explain why some flight controllers use three IMUs?

This could help:

And the docs here: