You can remove Newsletter Tab from the Customer account Dashboard in Frontend.
When you log in with your credentials, You will redirect to the Customer Dashboard page of the site and you can see a list of available Tabs are available to the left sidebar area.
If you don’t want to display Newsletter Tab from the left sidebar, You need to create a layout XML file to remove it from the Customer Profile.
Path:app/design/frontend/{VendorName}/{themename}/Magento_Newsletter/view/frontend/layout/customer_account.xml
<?xml version="1.0"?>
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="customer-account-navigation-newsletter-subscriptions-link" remove="true"/>
</body>
</page>
customer-account-navigation-newsletter-subscriptions-link is the block name of the Newsletter link display in Customer Profile.
You need to remove that block using the customer_account.xml file in your theme or module level.
Clear the cache and refresh the page. A link will be removed from the Customer Account Page.
If you want to remove link from the Admin Panel check the link, Newsletter Tabs from Admin Panel
Check All other frontend sidebar navigation links details, Navigation links