耳機充電問題，用5V2A充5V1A，會容易壞嗎？

No.

Many power sources (like charger or power bank) are dynamic. So the label generally means "up to". 2A is usually for fast charging. So if a device does not support fast charging, the amperage will be reduced.

So a 5V2A power source will only transmit 5V1A to the headset because of the limitation by the headset.

沒有關西，充多少電是受者主導，等同你吃多少碗飯是你自己控制