So today my Model 3 LR FSD got rear ended

I was driving on the freeway at 65mph and there was a chair in the middle of the road. The car in front of me dodged the chair last minute into another lane. I couldn’t change lane due to oncoming traffic on both sides so I pressed on the brake pedal. My car came to a complete stop & avoided hitting the chair but then bam I got rear ended. The other driver was very cooperative and apologetic. He is from Canada and was in a rush to catch his flight. We exchanged driver license, plate numbers, and took pictures. He didn’t have his insurance information as his car is a rental

(he will update me once he get a hold of it). I called highway patrol after the incident and an officer dispatched to do an incident report. Since the driver is from out of the country I’m not sure how this would work :/ I’m thinking I will work with the rental car’s insurance directly.
My car is dented in the back near the Tesla logo, and the body work panels are all messed and not aligned from back to front on the right side of the car. I hope the sensors are not affected.
I live in California, I want to ask what is the general process for repairing the Tesla? Time span? Any tips?
As far as diminished value, what do I need to do? Wait until the car is finished repair and proceed? Any recommendation for a good DV appraisal? Do I need a lawyer?
For Loss of Use process. Do I need to reject car rental offer from the other party’s insurance to claim LOU? How do I proceed about this?
Please help me out. I’m pretty overwhelmed and bummed out about my baby. Only have it for 5 months
