Yes you can remove JQuery Migrate to speed up the loading of your page on the client side.
What is jQuery Migrate?
The jQuery Migrate module (jquery-migrate.min.js) is a javascript library that allows you to preserve the compatibility of your jQuery code developed for versions of jQuery older than 1.9. JQuery Migrate also allows developers to detect deprecated code that is no longer supported by the latest jQuery libraries and to adapt it according to the newest versions of jQuery 1.9 and higher.
PHP code to disable jQuery Migrate in WordPress
This is the code I'm using for my clients and it is the right way to remove it properly on the client side without affecting any other components in the WordPress Dashboard. Grab this code and paste it in your functions.php file to remove the JQuery:
/**
* Disable jQuery Migrate in WordPress.
*
* @author Guy Dumais.
* @link https://en.guydumais.digital/disable-jquery-migrate-in-wordpress/
*/
add_filter( 'wp_default_scripts', $af = static function( &$scripts) {
if(!is_admin()) {
$scripts->remove( 'jquery');
$scripts->add( 'jquery', false, array( 'jquery-core' ), '1.12.4' );
}
}, PHP_INT_MAX );
unset( $af );
Hope this helps!