Yes, this is possible by using a Pre-User Registration Action. When using a Pre-User Registration Action, you will have better control over how you prefer to restrict sign-ups to your users.
In first place, thank you for your quick answer, it helped a lot.
I was wondering whether the event parameter in the hook has any property that allows to differentiate sign ups created through the dashboard from the ones done through the sign up page in order to allow only the first case.
Unfortunately, it’s not possible to differentiate signups from the Dashboard versus the sign up page. However, I would like to offer an idea that may work.
As a workaround, you could use the Auth0 Management API to create a user with a custom user_metadata value.
Then in your Pre-User Registration Action script, you could conditionally check if the user satisfies this value, and proceed with your logic accordingly.
This way, you could differentiate sign ups from your sign-up page and create user requests. But note that the Auth0 Dashboard will not have any way to create users with user_metadata values.