Well, for that purpose you don't need the technical innards of DJI to teach what you want to teach. I'd recommend getting all these details for Betaflight, the Flight Controller used in most homebuilt quads.
Ask Google: "what is the pid loop frequency for betaflight"
Answer:
AI Overview
In Betaflight, the PID loop frequency is the rate at which the PID loop computations are performed, which is the math that controls flight. The frequency is usually locked to the gyro's optimal frequency, which depends on the gyro. For example, the MPU6000 uses 8KHz, while the BMI270 uses 3.2KHz. However, the PID loop frequency may need to be adjusted depending on the motor protocol and board type:
dshot300: If you try to set the PID loop frequency to 8KHz, it may reset to 4KHz because dshot300 doesn't send updates fast enough to use 8KHz. 4KHz is recommended to save CPU time.
F3 board with SPI: Use 8KHz.
F3 board with I squared C: Use 4KHz