Retirement tax questions

I really love this answer - I've been tearing my hair out about how to report in Turbotax earnings from return of an excess contribution. The ideal, and seemingly the cleanest way for me to do this would be, as you say, to create a 1099-R and report the earnings that way. I've got to ask, are you absolutely certain that this is legal, since I won't be receiving the "real"  1099-R until January 2022? You say in your response that I can simply "ignore the 1099-R when it comes" (there are no withholding issues with my situation). What does the IRS do when I "report" a 1099-R and they don't have a matching one? If they really don't care, and if that's the only way I can report these earnings, then thank you! But I'm just a little nervous. Can you please help to assuage my concerns? Thank you!