I need to remove two parts of a your tube url and replace them

watch?v= needs to be /embed/
and &feature=youtu.be needs to just be removed.

Previously I had a stip replace which worked fine on Iphones
this code was

          <?php
$url = get_post_meta( get_the_ID(), 'wpcf-item-video', true );
$my_var = '/embed/';  
$url = str_replace("watch?v=", $my_var, $url );
 ?>
<iframe src="<?php echo $url ?>?&theme=dark&autoplay=1&keyboard=1&autohide=1" height="300px" frameborder="0" gesture="media" allowfullscreen=""><style> .ytp-title{display:none;}</style></iframe>

However then I found I also need to remove the &feature=youtu.be so I did this

     <?php
  $phrase  = get_post_meta( get_the_ID(), 'wpcf-item-video', true );
    $youtube = ["watch?v=", "&feature=youtu.be"];
    $replaced   = ["/embed/", ""];
    $newPhrase = str_replace($youtube, $replaced, $phrase); 
     ?>
    <iframe src="<?php echo $newPhrase ?>?&theme=dark&autoplay=1&keyboard=1&autohide=1" height="300px" frameborder="0" gesture="media" allowfullscreen=""><style> .ytp-title{display:none;}</style></iframe>

However, my latest code does not work. Can anyone explain why please?

Is there a better way of doing this?

Thanks