remove filter added by plugin with anonymous function

Question

Just for testing, I created a plugin with this

add_filter( 'woocommerce_checkout_fields' , function( $fields ) {
unset($fields['order']['order_comments']);
return $fields; } );

Now, I would like to remove it with functions.php file in child theme. The problem is anonymous function, so cannot just call remove_filter. Don't ask me to create a function with name, because I am working on a project, which I need to remove that filter without changing the plugin code.

I see some threads about this, but they are old, and not working. Any idea for completing this task, please?

Thanks.