Change WooCommerce checkout field order: https://www.damiencarbery.com/2019/02/change-woocommerce-checkout-field-order/ Changing the WooCommerce checkout fields display order is much simpler and more robust with the use of a 'priority' element in the field definition.

wc-house-num-field.php

<?php
/*
Plugin Name: Add House Number field (WooCommerce)
Plugin URI: https://businessbloomer.com/woocommerce-add-house-number-field-checkout/
Description: Add a House Number field to WooCommerce checkout.
Author: Rodolfo Melogli & Damien Carbery
Version: 0.2

*/

add_filter( 'woocommerce_checkout_fields' , 'bbloomer_add_field_and_reorder_fields' );
 
function bbloomer_add_field_and_reorder_fields( $fields ) {
    // Add New Fields
    $fields['billing']['billing_houseno'] = array(
	'label'     => 'House Number',
	'placeholder'   =>'House Number',
	'required'  => true,
	'class'     => array('form-row-last'),
	'clear'     => true,
	'priority'  => $fields['billing']['billing_address_1']['priority'] + 5,
	);
 
    $fields['shipping']['shipping_houseno'] = array(
	'label'     => 'House Number',
	'placeholder'   => 'House Number',
	'required'  => true,
	'class'     => array('form-row-last'),
	'clear'     => true,
	'priority'  => $fields['shipping']['shipping_address_1']['priority'] + 5,
	);
	
	// Remove Address_2 Fields
	unset($fields['billing']['billing_address_2']);
	unset($fields['shipping']['shipping_address_2']);
	
	// Make Address_1 Fields Half Width
	$fields['billing']['billing_address_1']['class'] = array('form-row-first');
	$fields['shipping']['shipping_address_1']['class'] = array('form-row-first');
 
	return $fields;
}