Yeah, a Wifi/Mobile Data system makes sense.
You mention that you upload smartphone photos and video when you get home at night and that makes sense too but there is a difference between some smartphone videos and photos and what could be potentially be hundreds of gigabytes of dash cam video, which could be a problem for some.
I think what you propose is more viable for some and thanr others. So, I'm very envious of your Verizon FiOS. You have no idea! It's a long story but up here on my little mountain the very fastest internet service available to me is 3 Megabit DSL!. It really sucks! I could get high speed cable two houses down the road which is about a half a mile away. Basically, despite promises made to get their foot in the door here in Vermont the major internet providers in the area won't spend the money to bring in the connections because they claim the housing density is too low. This is a statewide problem for many out in the countryside. So, many small towns like mine are banding together into what are called CUDS (Communications Union Districts) and by combining resources we will be building and operating our own fiber networks. The recent good news has been the Biden administration's infrastructure bill is providing major funding for projects like this and this will make the whole thing come together better and sooner. Eventually, we will get high speed fiber but it is still maybe two or three years away from coming to fruition; possibly less with the new funding.
