Changing the pointing of assets from old server to new server

Usually scripts and styles are loaded with wp_enqueue_script or wp_enqueue_style in the theme’s functions.php. That’s the most common scenario.

This function takes an $src parameter which is the absolute URL to the resource, and the best practice is to use get_stylesheet_directory_uri to retrieve the URL to the folder containing the script. This way, if the site is moved, the URL will change with it.

It might be that those were hardcoded strings. That’s why they’re still the old ones.

See examples below
https://developer.wordpress.org/reference/functions/wp_enqueue_script/#user-contributed-notes

Scripts and styles loaded from a plugin should use plugins_url in the $src parameter.
wp_enqueue_style( 'prm_style', plugins_url('/assets/style.css', __FILE__ ) );