Hi Leo, no there is still no option to turn off the reviews function from within the Vantage admin dashboard (and no immediate plans for it at this time), so yes this would require customization on your part if you were looking to remove it.
Our recommendation for any changes to the default theme would be to create a
child theme, which is going to save you from losing all of your changes in the process of an upgrade. If the changes are not made this way then yes you would expect to lose all the changes as soon as the theme is updated. Thanks.