Welcome to the Auth0 Community!
Having both Passwordless and Username/Password Connections for one application is currently not supported out-of-the-box, the main reason being that users can have multiple Auth0 accounts under the same email address, via different Connections. This way, a user might have an account in a Passwordless Connection and then create another account in a Username-Password DB.
A Passwordless connection is a distinct connection type and you cannot set a Database to be Passwordless in this sense, as it’s the equivalent of a DB, Social Login Connection or an Enterprise Connection.
On a different note, the flow that you described could be achieved if not relying solely on pre-built Auth0 integrations. It would be possible to create a custom UI in your application that checks the authentication methods of the user and the connection_id of the Connection from which they are trying to login. Based on that logic, your can create a custom flow that prompts the user for a specific Authenticator and also implement User Account Linking - Auth0 Docs to handle cases where users have multiple accounts under the same email address. The complexity of this built quickly rises to accommodate all possible scenarios.
Allow me to share some additional resources that support the information provided, or that might prove useful on this topic:
- Support Passwordless & Password in Universal Login;
- How to support password and passwordless?;
- Use both Passwordless and Password in Universal Login;
- Passwordless Connection type.
Hope this helped, please do not hesitate to reach out to us in the future, for any other issues or requests.
Have a great one!
Gerald