My guess is was not much more than $2k, I had a very similar level of damage on a Model S - (I was stopped on the freeway due to heavy traffic, Hyundai behind me wasn't paying attention and braked too late). The hatch they just bondo and repaint, they won't replace the entire hatch for that little bit of damage - I had very similar amount of damage on the hatch.
I had replaced the reinforcement bar with a hitch (OEM Tesla for S / X), and that thing is a tank, not sure if the Y's hitch is similarly built but while the bumper cover was severly damaged like yours, and needed complete replacement, the hitch didn't look like it had a scratch on it, I was even able to use it with a bike carrier and two bikes without issue, but I had it replaced anyways just in case. My total repair cost was $2,500 including a new hitch, new bumper cover, one new USS sensor, and repairing / repatining the hatch. Oh and $85 to repair the trunk latch that didn't fail until 3 months after the accident. The hitch was I think $300, the bar would likely be cheaper so even if you have to replace the bar it's not that much (it's not a sophisticated part by any means).