The deadline to file the 2021 tax return to claim any missed stimulus payments for the Recovery Rebate Credit was April 15, 2025.
If you did not file a return for the 2019 or 2020 tax years, you will not be eligible to claim the Recovery Rebate Credit, due to the deadline to claim the credit.
You may file a 2019 and 2020 tax return, if required to do so, but, this credit will not be available.