Get prefix from multiple wordpress sites with different databases with external script

I am trying to get the prefix of multiple databases of wordpress installations with different prefixes. But failing to do this and is getting me only the first table prefix for all files:

Folder structure (basic - has all required wordpress files):

home:
+---cpanel1
|   \---public_html
|       +---wp-load.php => $table_prefix = 'wp1_';
+---cpanel2
|   \---public_html
|       +---wp-load.php => $table_prefix = 'wp2_';
\---cpanel3
    \---public_html
        +---wp-load.php => $table_prefix = 'wp3_';
+---get_prefixes.php

Script get_prefixes.php (PHP):

$myfile = '/wp-load.php';
class execute_sql_code {
    public function __construct($myfile) {
        $this->main_work($myfile);
    }
    public $cpanels = array(
            'cpanel1',
            'cpanel2',
            'cpanel3'
    );
    public function main_work($myfile) {
        foreach ($this->cpanels as $cpanel) {
            $the_file = $cpanel.'/public_html'.$myfile;
            var_dump($the_file);
            require($the_file);
            global $wpdb;
            var_dump($wpdb->prefix);
        }
    }
}
new execute_sql_code($myfile);

var_dump($the_file) => OUTPUTS CORRECTLY every path.

var_dump($wpdb->prefix) => OUTPUTS WRONG wp1_ for each iteration:

CURRENT OUTPUT:

Iteration 1 => cpanel1/public_html/wp-load.php => $wpdb->prefix = wp1_

Iteration 2 => cpanel2/public_html/wp-load.php => $wpdb->prefix = wp1_

Iteration 3 => cpanel3/public_html/wp-load.php => $wpdb->prefix = wp1_

EXPECTED OUTPUT:

Iteration 1 => cpanel1/public_html/wp-load.php => $wpdb->prefix = wp1_

Iteration 2 => cpanel2/public_html/wp-load.php => $wpdb->prefix = wp2_ // normal

Iteration 3 => cpanel3/public_html/wp-load.php => $wpdb->prefix = wp3_ // normal

via Chebli Mohamed