No high-quality body shop in the world would quote repairing that damage without seeing the car. Your quote from the first shop has a lot of line items about the door, including (apparently) replacing the door hinges, which would indicate that there was a lot of force applied to the door and resulting damage, that isn't obvious even from the pictures.So I've just got another quote from another approved bodyshop. They haven't seen the car in the person but the guy on the phone is adament they can fix the sill - cost is 1800, so much much cheaper, unsurprisingly. Not sure which way to go with it.
I'm guessing that for 1800, you'll get a repair that's 90% as good as the full repair. Things like the door will get repaired and possibly repainted in-place; It'll look fine but the panel gaps around it may not be as good as they were before. I'm not sure how they'll repair the rocker panel but it probably won't be using a Tesla-approved method. It'll probably look good, and won't be noticeable as a repair at a glance.
I actually like body shops like that; I had one do a repair on my 2012 Mazda MX-5 Miata. I didn't need a perfect repair on a 10 year old car, but I did need one that looked good - and they did an amazing 95% job that was vastly cheaper than the 100% job.