Retirement tax questions

The $6000 funds contributed to the IRA were non deductible due to high income. The $6000 contributions made were after tax dollars. The funds were then converted to a Roth (backdoor Roth process) so a 1099-R was generated for that distribution with a distribution code 2 (early distribution with exception). Line one on the 1099-R was $6000 for gross distribution and line 2 was $6000 taxable amount. Taxable amount not determined box was checked. Seems like I could file form 8606  and have the distribution become non taxable since I was using after tax dollars for the contribution and the fact they were non deductible. Do you agree or is there something else I need to know to make the determination about whether the distribution s taxable or not? All of the transactions occurred in calendar year 2021.