You will have to be within near full 4G coverage all the time first of all, thats the main thing aside for the amounts of data.
Not so much of a problem if you dont move, more of a problem if you are on a popular mast and it throttling peoples speed to deal with things.
A single dashcam generate about 100 MB every minute it record, so thats 6000 MB ( 100 MB X 60 minutes ) = ( 6000 MB / 6 gigabyte ) in one hour, calculating with that for a 12 hour time period you get 12 hours X 6000 MB / 6 GB/h = 72.000 MB / 72 Gigabyte of data,,,,,, and remember thats just for one mediocre 1080p dashcam and me low-balling, higher bitrates / resolutions will of course mean even larger files.
I think thats more than are shifted thru my 1 gbit cable connection in a month, and i spend much ( too much ) time in front of the computer.
For that BV camera at full tilt if thats what it transmit, you are looking at 150 GB - 200 GB for those 12 hours i assume.
There is of course also the thermal aspect, i would not attempt this on a day with the sun out or for that matter higher comfortable summer temperatures.
There is a reason constant recording full bitrate / FPS are not recommended or done by most dashcams, latest heat combating options are time lapse / low bitrate 1080/30 and on the hardware remote dashcams with a main unit remote from the camera / s so it dont have to sit and cook in the sun.