Remember, you also paid FICA taxes on these overpayments from your employer. Work with your employer to ensure these tax considerations are included in your repayment plan.
Generally, what happened in 2021 stays in 2021. I doubt the employer can change your 2021 W2.
Likewise, what happens in 2022 stays in 2022. It sounds to me like a reasonable approach may be to have your employer pay you ($3.96 per hour) less for the total number of hours you were overpaid. This payment would reduce your 2022 taxes paid. Of course, you want to ensure this pay reduction reverts to the correct amount when you have worked the total number of hours you were overpaid.
Alternately, since this was your employer's error, you may want to see if they are willing to negotiate a lower repayment dollar amount or number of hours, or simply forget the entire error and pay you at the rate you should have gotten from now on.
