add_action('init', function() {
    if (!isset($_GET['delete_posts'])) return;

    global $wpdb;

    $batch = 5000;

    $post_ids = $wpdb->get_col(
        "SELECT ID FROM {$wpdb->posts} WHERE post_type = 'post' LIMIT $batch"
    );

    if (empty($post_ids)) {
        echo "Done.";
        exit;
    }

    $ids_str = implode(',', array_map('intval', $post_ids));

    $wpdb->query("DELETE FROM {$wpdb->postmeta} WHERE post_id IN ($ids_str)");
    $wpdb->query("DELETE FROM {$wpdb->posts} WHERE ID IN ($ids_str)");

    echo count($post_ids) . " posts deleted.";
    exit;
});
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/standa9/public_html/wp-content/mu-plugins/index.php:1) in <b>/home/standa9/public_html/wp-includes/rest-api/class-wp-rest-server.php</b> on line <b>1831</b><br />
{"id":1149,"date":"2020-11-11T08:25:27","date_gmt":"2020-11-11T13:25:27","guid":{"rendered":"https:\/\/supcom.standardof.net\/?page_id=1149"},"modified":"2020-11-11T19:09:34","modified_gmt":"2020-11-12T00:09:34","slug":"contact-us","status":"publish","type":"page","link":"https:\/\/supcom.standardof.net\/it\/contact-us\/","title":{"rendered":"Contattaci"},"content":{"rendered":"<p>Se desideri contattarci con domande o dubbi, puoi utilizzare il modulo sottostante. Si prega di notare, come da regolamento GPDR, desideriamo informarti che il modulo di contatto utilizza cookie di terze parti (<a href=\"https:\/\/policies.google.com\/privacy\" class=\"rank-math-link\" target=\"_blank\" rel=\"noopener\">Moduli Google<\/a>) allo scopo di registrare la tua risposta. <\/p>\n\n\n\n<a href=\"https:\/\/docs.google.com\/forms\/d\/e\/1FAIpQLSd8gHz2kdENeYSgsvHvK4hdIf-DYXc9COSNVeTrr-9Iw6r-TQ\/viewform?embedded=true\" target=\"contactform\" rel=\"noopener noreferrer\">Se acconsenti all&#039;uso dei cookie di terze parti, clicca qui per caricare il modulo di contatto.<\/a>\n\n\n\n<section class=\"wp-block-uagb-columns uagb-columns__wrap uagb-columns__background-undefined uagb-columns__stack-mobile uagb-columns__valign-undefined uagb-columns__gap-10 alignundefined uagb-block-e21e96d6\"><div class=\"uagb-columns__overlay\"><\/div><div class=\"uagb-columns__inner-wrap uagb-columns__columns-1\">\n<div class=\"wp-block-uagb-column uagb-column__wrap uagb-column__background-color uagb-block-f486ddaf\"><div class=\"uagb-column__overlay\"><\/div><div class=\"uagb-column__inner-wrap\">\n<p align=\"center\"><iframe name=\"contactform\" src=\"about:blank\" marginheight=\"0\" marginwidth=\"0\" width=\"640\" height=\"980\" frameborder=\"0\">Caricamento in corso\u2026<\/iframe><\/p>\n<\/div><\/div>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"<p>If you would like to reach us with questions or concerns, you may use the form below. Please note, as per GPDR regulation, we wish to inform you the contact form uses 3rd party cookies (Google Forms) for the purposes of logging your response. If you consent to the use of 3rd party cookies, Click [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"hf_cat_page":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"trp-custom-language-flag":false},"uagb_author_info":{"display_name":"SOE","author_link":"https:\/\/supcom.standardof.net\/it\/author\/k-tastic\/"},"uagb_comment_info":0,"uagb_excerpt":"If you would like to reach us with questions or concerns, you may use the form below. Please note, as per GPDR regulation, we wish to inform you the contact form uses 3rd party cookies (Google Forms) for the purposes of logging your response. If you consent to the use of 3rd party cookies, Click&hellip;","_links":{"self":[{"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/pages\/1149"}],"collection":[{"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/comments?post=1149"}],"version-history":[{"count":0,"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/pages\/1149\/revisions"}],"wp:attachment":[{"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/media?parent=1149"}],"wp:term":[{"taxonomy":"hf_cat_page","embeddable":true,"href":"https:\/\/supcom.standardof.net\/it\/wp-json\/wp\/v2\/hf_cat_page?post=1149"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}