Change post author to subsite admin if the author is super admin

code.php

<?php

add_action( 'admin_init', 'change_author_cb' );
function change_author_cb() {
    
    //$sites = wp_get_sites();
    // Set super admin ID here
    $super_admin_id = 1;
    
    //foreach( $sites as $site ){
    for( $i = 2; $i <= 10; $i++ ) {
        //if( $site['blog_id'] == 1 ) continue;
        
        switch_to_blog( $site['blog_id'] );
        
        $args = array(
                'posts_per_page'   => -1,
                'post_status'      => 'publish',
                'post_author'           =>  $super_admin_id,
        );
        $posts = get_posts( $args );
        
        $admin = get_user_by( 'email', get_bloginfo( 'admin_email' ) );
        
        foreach( $posts as $post ){
            $my_post = array(
                'ID'           => $post->ID,
                'post_author'       => $admin->ID
            );
            wp_update_post( $my_post );
        }
        
        restore_current_blog();
        
    }
    
}