so for the passwordless login, you don't really know if the user is signing in or signing up before they enter their email.

This means that you will have to show them to enter their name after their enter their email and dynamically show the field to enter their name after. In this case, you can send the name info in the create code API (via the pre API hook option) and then store that against the generated preAuthSessionId. Then in the consume code API, you get the preAuthSessionId and fetch the stored name.

Alternatively, you can first complete the whole login process, and you get a createdNewUser boolean after code consumption. If that boolean is true, you can redirect the user to a screen asking them their name.