Since the IRS already adjusted your original 2020 tax return there is no need to file an amended return for the adjustment. You file the amended tax return to change your dependency to being claimed as a dependent.
See this TurboTax support FAQ on amending a tax return originally completed and filed using the 2020 TurboTax editions - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-return/01/27439
The 2020 amended tax return can only be printed and mailed to the IRS since e-filing was closed for new tax returns after October 15, 2021.
