Right. The amount that was impermissibly deposited into the 401(k) became an regular contribution to the IRA when the 401(k) was rolled over to the IRA and treated as such on your 2021 tax return which can be returned before the due date of your 2021 tax return, including extensions (October 15, 2022) as long as you timely filed your tax return or requested a filing extension. That amount must also be reported as income on the 2021 tax return. If the employer does not correct the W-2, you would report the excess 401(k) contribution as miscellaneous income.
