Item 1 -- this is a learning experience for OP. Since COVID, all of the major rental car companies have had supply issues. The ONLY reliable place to get a car is at an airport location. Especially after working hours/ evenings/ nights. Local rental outlets, like HLEs, are really intended for local daytime activity (cars in the shop, neighborhood people). It's too bad that the cost is that much higher at the airport compared to the HLE, but with planning ahead, some of these costs can be reduced.

Item 2 -- this is less clear to me. I know that customers are responsible for body damage (dents, scrapes) and tires. But a part of the car falling off without any contact may be a gray area. The price also seems excessive for an OEM body part. If it was an aftermarket wheel cover, I would absolutely refuse to pay. Still, overseas locations are brutal about damage claims. Many credit cards offer coverage for rental cars. Amex has a wonderful supplemental policy at $15 per rental. And if all else fails, your own automobile policy should cover this claim less your deductible.