@giovannitirloni it somewhat depends on the use case, but there are good reasons to template annotations and there are good reasons to template the notification. I’ve written a blog post about this here.
The general advice is that if you are changing how alerts are presented in a notification, template the notification. If you are adding information about an alert (i.e. explaining what it means and how to respond to it) then template custom annotations, such as the Summary and Description annotations.