If you could not be claimed as a dependent on either the 2020 or 2021 tax returns then you have to amend each of those returns and complete the Recovery Rebate Credit (stimulus) section.
The Economic Impact Payments (stimulus payments) were only issued in 2020 and 2021.
See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
