To report the earnings on the excess contribution, you should enter a Substitute form 1099-R and enter it on your 2020 tax return. You will see an option for this when you see the screen Tell us Which 1099-R You Have.
Enter in box 1 the distribution amount. In box 2 enter the earnings. Enter code "P" in box 7. Work through the questions in TurboTax after you entered the 1099-R until you see a question regarding why you made the distribution, to which you will respond it was a return of an excess contribution.