Hi,
You can change the text using Loco Translate: How to change any static text - HivePress Help Center.
There is no simple solution for changing the place of the notification, but a possible workaround can be to use the registration page instead of the modal. You can use this code snippet and change the trigger from #user_login_modal to #user_register_modal. You can also create a custom page in WordPress > Pages and add the User Registration Form block there. This will solve the issue since, when the form is placed inside a regular page, it automatically scrolls to the top if there’s an error or a success message.
Hope this helps