di.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <virtualType name="Magento\Newsletter\Model\Session\Storage" type="Magento\Framework\Session\Storage">
        <arguments>
            <argument name="namespace" xsi:type="string">newsletter</argument>
        </arguments>
    </virtualType>
    <type name="Magento\Newsletter\Model\Session">
        <arguments>
            <argument name="storage" xsi:type="object">Magento\Newsletter\Model\Session\Storage</argument>
        </arguments>
    </type>
    <type name="Magento\Newsletter\Helper\Data">
        <arguments>
            <argument name="frontendUrlBuilder" xsi:type="object">Magento\Framework\Url</argument>
        </arguments>
    </type>
    <type name="Magento\Customer\Api\CustomerRepositoryInterface">
        <plugin name="update_newsletter_subscription_on_customer_update"
                type="Magento\Newsletter\Model\Plugin\CustomerPlugin"/>
    </type>
</config>