USB 3.0 - 3.1 ASO are by far the fastest USB standards, but a camera can not offload that fast anyway, the camera probably just have USB 1.0
When i connect a camera ( ACTION ) to my computer USB 3.0 i just get 15 MB/s or so transfer speeds, if i take the card out and put it on my USB 3.0 card reader i get the full 90 MB/s that the card support.
Same goes with my phone with a USB C interface connected to a USB 3.0 plug, trying to copy 3 GB of pictures to the memory card in the phone ( Toshiba U3 / 30 - 40 MB/s write speed ) it take half a day.
Taking out the Toshiba card and putting it in my card reader i can copy the same 3 Gb pictures to the memory card in minutes.
So my phone ( UMI Z ) seem to have the same issues that cameras have when you use them as mass storage devise.
So i always recomend taking the memory card out and use a good card reader on a fast USB port, my old USB reader probably just USB 1.1 was a nightmare, the new USB 3.0 Kingston card reader changed that a lot.