1. is of course protected by law. After you deposit foreign currency in the bank, you form a deposit contract relationship with the bank, which is protected by the laws of China.

2. At present, China's deposit interest rate (whether foreign currency or RMB) is determined by the People's Bank of China, and commercial banks cannot independently set interest rate standards. The specific basis of the change is very complicated, involving currency liquidity, international exchange rate, foreign exchange reserves and so on. I'm not sure I can answer you blindly.

At present, the state-owned banks in China are one of the safest banks in the world. Of course, other domestic commercial banks are relatively safe. You can notice that most of their shareholders are state-owned enterprises. Banks in many countries in Europe and America are private, so the operational risks are relatively large.