Help Needed: Struggling to Set Up PHP Mailer for My Contact Form

<?php

// Read the form values
$success = false;
$successTxt = "";
$senderName = isset( $_POST['name'] ) ? preg_replace( "/[^.-' a-zA-Z0-9]/", "", $_POST['name'] ) : "";
$senderEmail = isset( $_POST['email'] ) ? preg_replace( "/[^.-_@a-zA-Z0-9]/", "", $_POST['email'] ) : "";
$subject = isset( $_POST['subject'] ) ? preg_replace( "/[^.-' a-zA-Z0-9]/", "", $_POST['subject'] ) : "";
$budget = isset( $_POST['budget'] ) ? preg_replace( "/^[A-Za-z0-9\-\.] $/", "", $_POST['budget'] ) : "";
$message = isset( $_POST['message'] ) ? preg_replace( "/(From:|To:|BCC:|CC:|Subject:|Content-Type:)/", "", $_POST['message'] ) : "";
$txt = "Client budget: " . $budget . "nn"  . $message . "nn" . "Regards,nn" . $senderName . " | " .$senderEmail;

// If all values exist, send the email
if ( $senderName && $senderEmail && $message ) {
  $mailTo = "dusan@webluence.digital"; // change it to your host mail for example (contact@yourdomain.com).
  $headers = "From: " . $senderEmail;
  $success = mail( $mailTo, $subject, $txt, $headers );
  $successTxt = "<p>



<p>What I Need<br>
I want to replace this script with a secure PHPMailer-based script. Hostinger has preinstalled PHPMailer, and I’ve been told it’s more reliable. I found an article about setting it up, but it’s too confusing for me as someone new to PHP.</p>

<p>This is what I have right now:<br>
</p><pre class="brush:php;toolbar:false"><?php
require 'vendor/autoload.php';

use PHPMailerPHPMailerPHPMailer;

$mail = new PHPMailer;

$mail->isSMTP();
$mail->SMTPDebug = 0;
$mail->Host = 'smtp.hostinger.com';
$mail->Port = 587;
$mail->SMTPAuth = true;
$mail->Username = 'sales@webfluence.digital';
$mail->Password = 'c;Ge?H9unUs#:T0J';
$mail->setFrom('sales@webfluence.digital', 'Dusan Walla');
$mail->addReplyTo('sales@webfluence.digital', 'Dusan Walla');

// Read the form values and sanitize them to prevent injection attacks
$senderName = isset($_POST['name']) ? preg_replace("/[^.-' a-zA-Z0-9]/", "", $_POST['name']) : ""; // Remove any characters that are not letters, numbers, spaces, dots, hyphens, or apostrophes
$senderEmail = isset($_POST['email']) ? preg_replace("/[^.-_@a-zA-Z0-9]/", "", $_POST['email']) : ""; // Remove any characters that are not letters, numbers, dots, hyphens, underscores, or @
$subject = isset($_POST['subject']) ? preg_replace("/[^.-' a-zA-Z0-9]/", "", $_POST['subject']) : ""; // Remove any characters that are not letters, numbers, spaces, dots, hyphens, or apostrophes
$budget = isset($_POST['budget']) ? preg_replace("/[^.-' a-zA-Z0-9]/", "", $_POST['budget']) : ""; // Remove any characters that are not letters, numbers, spaces, dots, hyphens, or apostrophes
$message = isset($_POST['message']) ? preg_replace("/(From:|To:|BCC:|CC:|Subject:|Content-Type:)/", "", $_POST['message']) : ""; // Remove any email headers to prevent header injection

$mail->addAddress('sales@webfluence.digital', 'Dusan Walla');
$mail->Subject = $subject;
$mail->Body = <<<EOD
Client budget: $budget

$message

Regards,

$senderName | $senderEmail
EOD;

if (!$mail->send()) {
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    echo "<p>



<p>Questions<br>
How do I replace this script with PHPMailer in the simplest way possible?<br>
Is there a step-by-step guide that breaks down what I need to do?<br>
How do I configure Hostinger’s SMTP settings in the script?<br>
Any help would be deeply appreciated! ?</p>

<p>Additional Resources<br>
Here’s the article I was referring to: How to Use PHPMailer for Secure Email Sending</p>

<p>Thank you in advance for your guidance! ?</p>