Issues after driving on Super Rocky trail in mountains

I was driving in the mountains last weekend, when Google Maps took me down an unmarked road that started off as a smooth dirt path, then slowly turned into small gravel, then ended up into full on rocks and small boulders you might see on a hiking trail. The change was so gradual I didn’t think to turn around and decided to keep going, until the rocks were so large in the road they started scraping and even banging the undercarriage a few times. Driving over the rocks was extremely bumpy, so I’m worried about any potential hidden damage it might have done.

I have since driven about 1,000 miles since that incident and the car feels overall okay, except I noticed a large plastic cover has become partially unhinged on the undercarriage, which I’m guessing is from banging into the rocks. I’m not sure if this part is important, it seems to just serve as a cover to the undercarriage; it extends about 1/3 of the car from the front. It makes a loud flapping noise when driving at speeds 75 mph.

Also recently, I noticed the car has sometimes been making some grinding/scraping noises when turning, or when braking. I’m guessing this is due to worn down brake pads from braking down all the slopes when driving through the mountains.

I would appreciate any insight you might have, and I’m going to a mechanic first thing tomorrow to get the car checked out. I know it’s hard to tell, but I would also appreciate your thoughts on a price estimate. Please let me know if you have any questions.