to ease your discomfort a little
The stimulus payment is intended to be an advance payment against an actual credit you will compute on your 2020 tax return. If your advance payment is LESS than what's computed when you file your 2020 return your refund will be increased or the amount owed will be reduced. But if your advance credit is GREATER than what's computed there appears to be no mechanism to either 1) repay the excess payment, or 2) recognize the excess amount as income.
