Create a custom module and follow the below step.

1. Create file di.xml on app/code/Vendor/Module/etc

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">	
	<type name="MagentoOfflinePaymentsModelCashondelivery">
        <plugin name="restrict_payment_on_shippingmethod" type="VendorModulePluginMethodList" disabled="false" sortOrder="10"/>
    </type>
</config>

2. Create file MethodList.php on app/code/Vendor/Module/Plugin

<?php 
namespace VendorModulePlugin;
 
use MagentoPaymentModelMethodAbstractMethod;
use MagentoQuoteModelQuote;

class MethodList
{  
    public function __construct(
        PsrLogLoggerInterface $logger,
        MagentoCheckoutModelSession $checkoutSession
    ) {
        $this->logger = $logger;
        $this->_checkoutSession = $checkoutSession;
    }

    public function aroundIsAvailable(
      MagentoPaymentModelMethodAbstractMethod $subject, callable $proceed)
    {
        $shippingMethod = $this->_checkoutSession->getQuote()->getShippingAddress()->getShippingMethod();
        // $this->logger->debug($shippingMethod);

        if ($shippingMethod == 'freeshipping_freeshipping')
            return false;

        return $proceed();
    }
} ?>