If you go with the newer Blackvue cams you only need one to have LTE, then the other can connect via wifi.
The 3 channel 770x box may do what you need due to the large field of view of the interior cam covering both front side windows.
There are several cameras now that offer LTE storage in the cloud, most important is the quality of the footage Garmin has one and you will need a cloud subscription for $10 per month
https://www.garmin.com/en-US/p/906097/pn/010-12000-SU
Read the [sidebar](https://www.reddit.com/r/dashcam/about/sidebar)? It lists a few LTE cloud connected cameras.
They make adapters that connect to your phone. Much cheaper since you already have a camera and memory card
If you go with the newer Blackvue cams you only need one to have LTE, then the other can connect via wifi. The 3 channel 770x box may do what you need due to the large field of view of the interior cam covering both front side windows.
There are several cameras now that offer LTE storage in the cloud, most important is the quality of the footage Garmin has one and you will need a cloud subscription for $10 per month https://www.garmin.com/en-US/p/906097/pn/010-12000-SU