function disable_embeds_init() {

    // Remove the REST API endpoint.
    remove_action('rest_api_init', 'wp_oembed_register_route');

    // Turn off oEmbed auto discovery.
    // Don't filter oEmbed results.
    remove_filter('oembed_dataparse', 'wp_filter_oembed_result', 10);

    // Remove oEmbed discovery links.
    remove_action('wp_head', 'wp_oembed_add_discovery_links');

    // Remove oEmbed-specific JavaScript from the front-end and back-end.
    remove_action('wp_head', 'wp_oembed_add_host_js');
}

add_action('init', 'disable_embeds_init', 9999);