Who was it that once said, "We tax income, not pieces of paper"?  Anyway, if the W-2 is wrong, you need to tell IRS, not just accept what some clerk at an insurance company who has never taken a tax course tells you.  I would have used a Form 4852, maybe, for 2021.  For now, on an amended return, just decrease the wages by the amount of the returned funds, and explain it in a paragraph or two.  And file on paper, which doesn't slow down the process more than three or four days.