The Mavic 3E/3T aircraft MicroSD slot is very difficult to access.  

With the ability to use a MicroSD card on the controller and fast transfer speeds between the aircraft and controller, it would seem logical that the imagery could be transferred to the controller MicroSD card when set up as portable storage.

This option does not seem to work

1.  The downloaded files from airframe to controller are in a root directory which is not viewable on the controller file system. - This limits the ability to transfer them from Internal storage to MicroSD

2. DNG files from Mavic 3E do not transfer to the controller.

2. I installed ES File explorer on the controller with the hope that I could "share" the airframe photos with ES File Explorer, which shows as an option when viewing the airframe album, but when attempting to copy the files to the controller MicroSD I receive "Auth failed" error...probably due to a root process.

This option availabilty might save DJI some aircraft replacement charges when the aircraft start showing up with broken dust covers on the back of the aircraft.

This option will also allow the MicroSD card on the controller to be used for constant removal to PC transfer.

Hi, there.
We are sorry for the inconvenience caused.
We will forward your feedback to the relevant team and see how we can do better with this problem.
Please wait for the update.
Thank you for your understanding as well.

DJI Natalia Posted at 11-6 23:13
Hi, there.
We are sorry for the inconvenience caused.
We will forward your feedback to the relevant team and see how we can do better with this problem.

Update:
We recommend that you remove the battery, and then insert and unplug the SD card will be more convenient.
1. The storage location of photos downloaded is: Internal Storage-DJI-com.dji.industry.pilot-Pilot Album
2. Currently, the controller does not support downloading photos in raw format, but only supports downloading photos in JPEG format and 1080P H.264 format video. If you shoot in RAW format, it is recommended to download it from the SD card directly.
3. Is there an error in using third-party software to copy files to the SD card of the controller? We recommend that you use the file manager that comes with the controller to copy the files to the SD card according to the above-mentioned file storage location.

If there is anything else that we can help with, please let us know.
Thank you for your support in advance.

One solution could be to just  plug the mavic to the USB C cable and transfer it to the computer that  way. Im not sure what speed you will get.