I'm also in the same position. TurboTax says I will receive my federal refund by 05/06/2022. I know that I need to wait until I receive my refund before I can file 1040X because it asks me about my exact return amount (and also according to the IRS website). I was wondering if it's okay to file it after the IRS deadline? How do I know the interest amount that I owe IRS in this case?
