Sorry you got bad advice. You needed to enter the full 2800 you got. It was right your tax due went up. You do owe it back. I didn't understand the rest of your post. If the IRS changes or amends your tax return they don't update Turbo Tax. I don't understand how your Turbo Tax data reflected any changes.
It is not taxable and you aren't paying it back. Your 2021 return starts out by assuming you didn't get any Stimulus payments so it gives you credit for the full amount and your refund was too high. Then near the end you enter how much you actually got so it only gives you the difference if any. So you don't get it again.
