You're not doing anything wrong. Your taxable income is already reduced for HSA contributions made through payroll. Box 1 on your W-2 doesn't include your contributions made. Your contributions, along with your employer's, are both reported on your W-2 Box 12 Code W. Neither are included in taxable income.
If, for some reason the contributions are being added to your income, revisit the HSA section in Deductions and Credits, and make sure you've reported that you were covered by a High Deductible Health Plan (HDHP) in 2024.
