Allow other roles to edit Notifications

You can overwrite the Notification post type capabilities. See the capabilities for specific roles.

In the example below, you are allowing everyone with an editor role or greater to manage the notifications.

add_filter(
    'notification/post_type/capabilities',
    function($capabilities) {
        return [
            'edit_post' => 'publish_posts',
            'read_post' => 'publish_posts',
            'delete_post' => 'publish_posts',
            'edit_posts' => 'publish_posts',
            'edit_others_posts' => 'publish_posts',
            'delete_posts' => 'publish_posts',
            'publish_posts' => 'publish_posts',
            'read_private_posts' => 'publish_posts',
        ];
    }
);

Please note that the capability the user has to have is unfiltered_html. Otherwise, the notification configuration won't be saved properly.