I would have a tab that points to your user profile table and is only visible when the user profile type is empty. All other tabs would be conditioned to show once the type is not empty. On that type screen, you can filter the screen where the email is the signed in user, so they will only edit their own row. I wouldn’t use a form, because forms add rows. You should already have an existing row so you only want to change the user type on that existing row. They should not need to enter an email again since they are already signed in. All you should need is a choice component for the user to select the type of user they are. Once they do, the tab will hide and the other tabs will show.
I recommend checking out this thread for a more details on how to do this.