You can delete your S Rank account directly inside the app:
This permanently removes your account from active systems and signs you out of the app.
Email supportsrank@gmail.com with the subject line Delete S Rank Account. Send the request from the email address attached to the account, or include your friend code and any other details needed to identify the account.
When an account deletion request is completed, we delete or remove access to the following items from active systems where applicable:
Subscription billing records remain with Google Play and are governed by Google's billing terms. Some backup copies may persist for up to 30 days before final removal.
Health Connect data is read on-device. Deleting your S Rank account does not remove the source data stored in Health Connect itself. To revoke access, open Health Connect settings on your Android device and remove S Rank access there.
Questions about account deletion can be sent to supportsrank@gmail.com.