I also suggest submitting a request to exercise your privacy rights (if applicable to your location): https://support.reddithelp.com/hc/en-us/requests/new?ticket_form_id=360001370251

According to Reddit's Privacy Policy (as of June 13, 2023), they need to verify that you have access to your Reddit account:

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.