Difficulty Overriding Magento 2 File

I am new to coding in Magento 2. I am trying to override a file using this guide https://webkul.com/blog/overriding-rewriting-classes-magento2/, and my file compiles without error, but changes don’t take place on the frontend. I have put the file in a Hello World module called MyTest. My di.xml file located at app/code/[My_Vendor]/MyTest/etc/di.xml is

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="MagentoCatalogPricingRenderFinalPriceBox" 
type="[My_Vendor]MyTestRewritePricingRenderFinalPriceBox" />
</config>

and my FinalPriceBox.php file which overwrites vendor/magento/module-catalog/Pricing/Render/FinalPriceBox.php and is located at app/code/[My_Vendor]/MyTest/Rewrite/Pricing/Render/FinalPriceBox.php is

<?php

namespace [My_Vendor]MyTestRewritePricingRender;

class FinalPriceBox extends MagentoCatalogPricingRenderFinalPriceBox
{

    public function _renderAmountMinimal()
    {
        $id = $this->getPriceId() ? $this->getPriceId() : ‘product-minimal-price-’ . $this->getSaleableItem()->getId();
    
        $amount = $this->minimalPriceCalculator->getAmount($this->getSaleableItem());
        if ($amount === null) {
            return ‘’;
        }

        return $this->renderAmount(
            $amount,
            [
                ‘display_label’     => __(‘As low as mytest’),
                ‘price_id’          => $id,
                ‘include_container’ => false,
                ‘skip_adjustments’ => true
            ]
        );
    }
    
}

?>

I am not sure what is going wrong. I do not see any new error messages, and I know that changing the original file does cause the changes I want on the frontend. I also know that the module is enabled and correctly prints Hello World on a test page. The guide did not have a composer.json file so my module doesn’t have one, and I am not sure if that could cause the problem. I was wondering if anyone had advice on what might be going wrong