Do while loop if username exists in php

username-exists.php

<?php
//  custom function for test only. You don't need to use this function if you use it with wordpress. 
//  Wordpress have already this function: https://developer.wordpress.org/reference/functions/username_exists/
function username_exists($user_login){
  $names = ['Razon', 'Razon-1', 'Razon-2', "Supu"];
  if(in_array($user_login, $names)){
    return $user_login;
  }else{
    return false;
  }
}

$name = "Razon";
$baseName = $name;
$i = 0;

while(username_exists($name)) {
    $name = $baseName .'-'. (++$i);
}

return $name;