If you didn't get the 3rd EIP Stimulus payment because your 2020 income was too high or it was reduced but your 2021 income is lower now, you can get it now as the Recovery Rebate Credit on 1040 line 30. The IRS just used your 2020 return to send the checks out fast. See Question 2 here,
https://www.irs.gov/newsroom/2021-recovery-rebate-credit-topic-c-eligibility-for-claiming-a-recovery...
