Income is reported when you actually receive it, so you have no IRA income to report for 2021.
But, you do need to file a penalty form 5329 with your tax return to report that you failed to take the RMD, but you took it as soon as you realized the mistake in January, and request a waiver of the penalty.
Then, since you are counting the January 2022 withdrawal as your 2021 RMD, you will need to take another withdrawal sometime in 2022 to satisfy the 2022 requirement. You will get one 1099-R next year reporting the total you withdrew in 2022. Remember that an RMD is not a specific transaction, it is just the minimum amount you must withdraw based on your age and account balance. You could always withdraw more. If your RMD was $5000, that would be satisfied if you withdrew $5000 on December 29, but it would also be satisfied if you withdrew $500 per month for living expenses, or if you withdrew $10,000 in June to buy a new car. You don't have to take an extra specific RMD withdrawal in December if you have already withdrawn the required amount (or more) during the year.
