Basic question about universal login flow

We currently use universal login which allows the user to switch to create account even it we start them in the login flow.

To be able to enforce iOS app age verification only when creating an account, we need to know when a user goes to the create an account flow. We cannot allow the user to transparently go from the login flow to account creation.

If it possible to use the Auth0 universal login flow and disable the create account option so that it does not appear. And have a separate flow initiated by the app that only allows account creation but not login?

Or is the only solution to create a native UI for login and account creation and use the Resource Owner Password Flow?

Thanks!