Sorry to see that. Having been rear-ended myself I feel the pain every time I see one of these posts.
It's hard to tell how much damage from pictures, but it seems like most of the damage is in the rear and it doesn't look as bad as it could have been. That said, I'm sure it'll be a lot more than it looks after a body shop disassemble things. Could the car still be driven? Having no idea what it looks like beneath the bumper and more importantly the floor area in the rear, I would guess $10k at the low end and over $20k on the high end.
When I was hit, the rear liftgate basically looked like yours, but my lower bumper (black section) was intact with only a couple of small punctures. The liftgate was displaced a bit but still functioned and I was able to drive the car for 2 months while I waited for the body shop to take it in. My repair bill was just under $7k (initial estimate was under $4k), but the body shop guy told me if the floor had been damaged, it would have easily been double.
Regarding the video, did you push the dashcam icon after impact? If not, it may or may not have been saved, based on what I've seen reported around here regarding dashcam footage from collisions. Saving the dashcam footage was the first thing I did when I got rear-ended, but the impact was moderate (neither my wife or I suffered any injuries) so I imagine my situation wasn't as stressful as yours. You need to pull out the USB drive in the glovebox and check the video files in there to see if the collision was recorded.
Good luck with getting everything sorted out.