Remove your comment history on Reddit as deleting an account does not do so. - GitHub - x89/Shreddit: Remove your comment history on Reddit as deleting an account does not do so.
Before we process a request from you about your personal information, we need to verify the request via your access to your Reddit account or to a verified email address associated with your Reddit account.
Also note from the Privacy Policy (as of June 13, 2023):
After you submit a request to delete your account, it may take up to 90 days for our purge script to complete deletion. We may also retain certain information about you as required by law or for legitimate business purposes.