@elliottm8 For 2021, if adding it increases your refund, don't bother filing unless the IRS is pursuing this Any refund is forfeit for failure to file timely. If you now owe, taking in any prior refunds, you'll need to amend and either send in payment and wait for the IRS bill for penalties and interest. This should be a little less then waiting for one bill for everything.
I don't know if Tuyrbotax still supports 2021. If not, you'll either have to complete the amendment manually or seek the aid of a tax pro. You can not add a 2021 W-2 to your 2025 return
