Based on the provided extracts, it is not possible to use the hosted pages to accomplish biometric authentication without creating an account beforehand and without any custom code. The extracts mention passwordless authentication using the WebAuthn specification, which requires adding the WebAuthn JavaScript to the page and following a specific flow for authentication (source: [Custom UI Advanced Integration](https://www.ory.sh/docs/kratos/bring-your-own-ui/custom-ui-advanced-integration)). However, the extracts do not mention any way to achieve biometric authentication using hosted pages without creating an account or without custom code.

The account signing in must exist. So the user must either create the account themselves and use their biometic key as the password or as an admin you must create the account for the user and send them a recovery email.