When you Donate a gift card, you have No Sale and No Write off. You made up that entry out of Nothing. If you intend to enter the Sale, which is Gross, you also need to Write it off, as if that is 100% discounted.

Then, the Card is used. That means the Actual Sale won't be paid. That means the Actual Sale is also Written off, the same as the Amount of the gift card is the Discount amount. This specific event might not be 100% discounted, of course.

You cannot Write Off Lost Profit; that is where people get confused. You are Forfeiting the right to profit. Your Lost revenue is offset completely, not Reported as if that is Real.

You already have Real Expense; goods and services, such as Payroll and Products are your real expense. It costs you  Nothing additional to give away a Gift Card, and nothing to Give away the sale to the value of that gift card.