As i understand it you cant really do anything quickly with a dashcam.
The wifi in them are pretty slow, the the clip that took you 3 min to record, its probably 5 min to DL to your phone.
Connecting the camera to a computer to use it as a card reader is also slow, but in this case if you just grab a file or two it dont really matter, but otherwise the transfer speed are often uder 20 MB/s where as in a good card reader you can get the full read speed of the memory card which are often up around 90 MB/s
Second as the dashcam are such a slow card reader, you might run into playback issues if you playback footage directly from the card in the camera, on the other hand my USB 3 card reader on a USB 3 port, i can playback directly from the card 4K/60 FPS footage recorded with 100 mbit bitrate.
I have never tried to DL a file from a dashcam over wifi, but i have tested if i was able to playback files on some cameras, but cant recall if that necessitated a DL of the file first or i was able to stream the file from the camera, and if so if the stream was still the original resolution of the recording. ( some cameras also record a low resolution video for faster playback ASO )
I made the test a while back demonstrating the transfer speeds with the dashcam - the provided USB card reader you often get with a dashcam, and finally my fast USB 3 card reader.
I have run a little test on my computer using various readers, from my default Kingston reader ( USB 3.0 ) on a USB 3.0 port, to factory provided readers, and finally using a dashcam ( A139 ) in mass storage mode. There is a huge difference in the speeds you get, my Kingston reader of course...
dashcamtalk.com