Magento 2 How to Update custom order attribute using REST API

I am using this –

extension_attributes.xml

<extension_attributes for="MagentoSalesApiDataOrderInterface">
        <attribute code="custom_sales_id" type="string" />
</extension_attributes>

di.xml

<type name="MagentoSalesApiOrderRepositoryInterface">
        <plugin name="custom_sales_id" type="CompanyNameModuleNamePluginApiOrderRepository"/>
 </type>

OrderRepository.php

<?php

namespace CompanyNameModuleNamePluginApi;
ini_set('display_errors',1);
error_reporting(E_ALL);

use MagentoSalesApiDataOrderExtensionFactory;
use MagentoSalesApiDataOrderExtensionInterface;
use MagentoSalesApiDataOrderInterface;
use MagentoSalesApiDataOrderSearchResultInterface;
use MagentoSalesApiOrderRepositoryInterface;
use MagentoFrameworkExceptionCouldNotSaveException;



/**
 * Class OrderRepository
 */
class OrderRepository 
{

    const CUSTOM_SALES_ID= 'custom_sales_id';

    /**
     * Order Extension Attributes Factory
     *
     * @var OrderExtensionFactory
     */
    protected $extensionFactory;

    /**
     * OrderRepositoryPlugin constructor
     *
     * @param OrderExtensionFactory $extensionFactory
     */
    public function __construct(OrderExtensionFactory $extensionFactory)
    {
       
        $this->extensionFactory = $extensionFactory;
    }

    /**
     * Add "custom_sales_id" extension attribute to order data object to make it accessible in API data
     *
     * @param OrderRepositoryInterface $subject
     * @param OrderInterface $order
     *
     * @return OrderInterface
     */
    public function afterGet(OrderRepositoryInterface $subject, OrderInterface $order)
    {
        $customSalesId = $order->getData(self::CUSTOM_SALES_ID);
        $extensionAttributes = $order->getExtensionAttributes();
        $extensionAttributes = $extensionAttributes ? $extensionAttributes : $this->extensionFactory->create();
        $extensionAttributes->setCustomSalesId($customSalesId );
        $order->setExtensionAttributes($extensionAttributes);

        return $order;
    }

    /**
     * Add "custom_sales_id" extension attribute to order data object to make it accessible in API data
     *
     * @param OrderRepositoryInterface $subject
     * @param OrderSearchResultInterface $searchResult
     *
     * @return OrderSearchResultInterface
     */
    public function afterGetList(OrderRepositoryInterface $subject, OrderSearchResultInterface $searchResult)
    {
        $orders = $searchResult->getItems();

        foreach ($orders as &$order) {
            $customSalesId = $order->getData(self::CUSTOM_SALES_ID);
            $extensionAttributes = $order->getExtensionAttributes();
            $extensionAttributes = $extensionAttributes ? $extensionAttributes : $this->extensionFactory->create();
            $extensionAttributes->setCustomSalesId($customSalesId );
            $order->setExtensionAttributes($extensionAttributes);
        }

        return $searchResult;
    }

    public function beforeSave(OrderRepositoryInterface $subject, OrderInterface $resultOrder)
    {
        foreach (['custom_sales_id'] as $field) {
            $value = $resultOrder->getData($field);
            $resultOrder->setData($field, $value);
        }
    }

}

custom_file.php

 $data_json = [
        "entity"=> [
            "entity_id" => 76,
            "customerId" => 61,
            "state" => "complete",
            "status" => "complete",
            "extension_attributes" =>[
                
                "custom_sales_id" => "test"
            ]
            
        ]
    ];
    echo $data_string = json_encode($data_json);
    $ch = curl_init("http://xyz/index.php/rest/V1/orders/create");
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "PUT");
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data_json));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json", "Authorization: Bearer " . $token));
    $result = curl_exec($ch);
    $result = json_decode($result, 1);
    echo "-----------update order----------------";
    echo "<pre>";
    print_r($result);

It showing response but not inserting into database
As I debug afterGet function not calling

public function beforeSave(OrderRepositoryInterface $subject, OrderInterface $order)
{
    $extensionAttributes = $order->getExtensionAttributes();
    $extensionAttributes = $extensionAttributes ? $extensionAttributes : $this->extensionFactory->create();
    $resultOrder->setData(self::CUSTOM_SALES_ID, $extensionAttributes->getCustomSalesId());
}

public function beforeSave(OrderRepositoryInterface $subject, OrderInterface $order) {
$extensionAttributes = $order->getExtensionAttributes() ?: $this->extensionFactory->create();
    if ($extensionAttributes !== null && $extensionAttributes->getCustomSalesId() !== null) {
        $order->setCustomSalesId($extensionAttributes->getCustomSalesId());
    }

    return [$order];