Create a directory in WordPress Multisite subsite directory

I am attempting to create a directory in a WordPress Multisite subsite directory.

The subsite directory is located at /home/site/site.com/wp-content/uploads/sites/site_id/ where site_id is the actual id# of the subsite.

I’m looking to create a directory under the site_id directory, and then add a file to that directory from elsewhere in my network.

Here is what I have so far:

// Get current site id
global $current_blog;
$shop_id = $current_blog->blog_id;    
// Create directory for current site if does not exist

if (!file_exists(WP_CONTENT_DIR . '/uploads/sites/' . $shop_id . '/new-directory/')) {
    mkdir(WP_CONTENT_DIR . '/uploads/sites/' . $shop_id . '/new-directory/', 0777, true);
}
//Copy download.php to new directory
$download_file = 'https://example.com/wp-content/plugins/new-directory/download.php';
$copy_download = 'https://example.com/wp-content/uploads/sites/' . $shop_id . '/new-directory/download.php';
if (!file_exists('https://example.com/wp-content/uploads/sites/' . $shop_id . '/new-directory/download.php')) {
    copy($download_file, $copy_download);
}

When I run this, I get a failed to open stream: No such file or directory on line 30. Line 30 is the copy($download_file, $copy_download); line.