If you used TurboTax Download for those years, then yes, you can ReFile those years.

If you used TurboTax Online, then you can ReFile 2021, 2022 & 2023. TurboTax Online 2020 is no longer available. However, you can still make adjustments to your return. This Canada Revenue Agency (CRA) page tells you all the ways to can change your filed return: https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/change...

This TurboTax FAQ tells you how to ReFile a return in TurboTax: https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/accounting-bookkeeping/file...