The deduction for repaid Social Security benefits (the negative amount in box 5) is an itemized deduction. If you take the standard deduction, then you do not get any itemized deductions, including the deduction for the repaid Social Security. So if you include it in your itemized deductions, but take the standard deduction, you would lose the deduction for the repayment.
You can take the credit instead of the itemized deduction, but there are some complications. TurboTax will not calculate the credit for you. You have to do all the calculations yourself.
To calculate the credit you have to recalculate your tax return for the year (or years) that you received the benefits that you repaid in 2023. You can't do that in TurboTax Online. If you used TurboTax Online for the earlier year you would have to download your .tax20yy data file, then use the CD/Download TurboTax software for earlier year to do the recalculation. You don't file the recalculated return, but you need the results of the recalculation to calculate your credit for 2023.
In addition, there is no way to enter the credit in TurboTax Online, because it's not covered in the TurboTax interview. It can only be entered in forms mode, which is only available in the CD/Download TurboTax software. So you would have to use the CD/Download software for 2023 as well.
