Hi,
I use this code to disable Rest API and prevent multiple page dublicates:
// Disable REST API
add_filter('rest_enabled', '__return_false');
// Disable diltres REST API
remove_action( 'xmlrpc_rsd_apis', 'rest_output_rsd' );
remove_action( 'wp_head', 'rest_output_link_wp_head', 10, 0 );
remove_action( 'template_redirect', 'rest_output_link_header', 11, 0 );
remove_action( 'auth_cookie_malformed', 'rest_cookie_collect_status' );
remove_action( 'auth_cookie_expired', 'rest_cookie_collect_status' );
remove_action( 'auth_cookie_bad_username', 'rest_cookie_collect_status' );
remove_action( 'auth_cookie_bad_hash', 'rest_cookie_collect_status' );
remove_action( 'auth_cookie_valid', 'rest_cookie_collect_status' );
remove_filter( 'rest_authentication_errors', 'rest_cookie_check_errors', 100 );
// Disable events REST API
remove_action( 'init', 'rest_api_init' );
remove_action( 'rest_api_init', 'rest_api_default_filters', 10, 1 );
remove_action( 'parse_request', 'rest_api_loaded' );
// Disable Embeds linkied with REST API
remove_action( 'rest_api_init', 'wp_oembed_register_route' );
remove_filter( 'rest_pre_serve_request', '_oembed_rest_pre_serve_request', 10, 4 );
remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );
// если собираетесь выводить вставки из других сайтов на своем, то закомментируйте след. строку.
remove_action( 'wp_head', 'wp_oembed_add_host_js' );
But if I delete this code from function.php of my theme it doesn’t help solve the problem with CF7 4.8.