You can make a backend workflow with a text field for email, then a “Return data from API” action, Search for Users:count > 0 , constraint email = [email field]. So it returns a yes/no depending on a User exists or not.
Then setup the App Connector to itself so you can call that workflow and return data:
Then when they type their email and hit ENTER do the backend workflow, the resulting yes/no is for you to reference on the conditions for each step 2/3
