The SDK 4.13 and DJI Fly does not support AEB for the Mavic Mini today
I built my own software method to use AEB with individual +/- EV settings. I use the GCD method from iOS to realize fast and save shootings. This method works with any aicraft or handheld.
I used set and get ShutterSpeed and the camera capability shutterSpeedRange to implement this function. You must pack it into a GCD method to handle the different shootings states.