How to implement the most basic use of Google reCaptcha v3

I am running a Wordpress site and want to protect a custom contact form with Googles reCaptcha v3. Sadly my code seems to be wrong and I couldnt find the problem, please help.

This is my Form

<?php
 // reCAPTCHA v3
 define('SITE_KEY', 'Key');
 define('SECRET_KEY', 'SCRT_KEY');

 echo '<script src="https://www.google.com/recaptcha/api.js?render=' . SITE_KEY . '"></script>';
?>

<form action="<?php echo get_home_url(); ?>/sent" method="POST" id="footer-form">

 <!--INPUT FIELDS HERE-->
 <input type="hidden" id="g-recaptcha-response" name="g-recaptcha-response" />

 <button class="button_1" type="submit">
  Send
 </button>

</form>

<script>
 grecaptcha.ready(function() {
  grecaptcha.execute("KEY IS HERE", {action: "homepage"})
  .then(function(token) {
   console.log(token);
   document.getElementById("g-recaptcha-response").value=token;
  });
 });
</script>

My form posts to this php file

// reCAPTCHA v3
define('SITE_KEY', 'KEY');
define('SECRET_KEY', 'SCRT_KEY');

$Response = file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=".SECRET_KEY."&response={$_POST['g-recaptcha-response']}");
$Return = json_decode($Response);

if($Return->success == true && $Return->score > 0.5){
 EMAIL CODE HERE
}

thats about it.. first part seems to work because my g-recaptcha field value got the session token

but the $Response is always false ( i think file_get_contents doesnt work?)

I hope someone can help me, also I dont want to use a PlugIn. Thanks

This code is adapted from this tutorial:

https://youtu.be/61QBrGpwQGg?si=TU3BUsN1RXN9jpmq

This guy had the same problem, but no solution:

Google recaptcha v3 success issue

The problem was that file_get_contents() had missing context...

Google Api only accepts POST requests. Needed stream_context_create()...