I’m trying to send userdata to mysql database using php. I want username to be cyrillic, and when i manually type the username in database, it is displayed correctly. But when I pass the data to database it`s stored like “Грумінг”

Here is file that proccess the registration of users: reg_query.php

<?php
session_start();
header('Content-Type: text/html; charset=utf-8');
     require_once __DIR__ . "/database/pdo.php";
     $username = $_POST['username'];
     $password = $_POST['password'];
     $email = $_POST['email'];
     $password = md5($password);
      
$sql = "SELECT username FROM `users` WHERE username='{$username}'";
$result = mysqli_query($con,$sql) or die("Query unsuccessful") ;
       if (mysqli_num_rows($result) > 0) {
         header("Location: login.php?msg=failed");
       } else {
$sql = "INSERT INTO `users` (`username`, `password`,`email`) VALUES (:username, :password, :email)";
     $params = [
         "username" => $username,
         "password" => $password,
         "email" => $email,
     ];
     $prepare = $pdo->prepare($sql);
     $prepare->execute($params);
     $pdo->lastInsertId();
     $lastInsertId=$pdo->lastInsertId();
      $_SESSION['login'] = true;
      $_SESSION['username']=$username;
      $_SESSION['password']=$password;
     header("Location: /cabinet.php");
}
?>

Here is connection file: pdo.php

<?php
  $host = "host";   
  $user = "user";   
  $password = "password";   
  $db_name = "db_name";   
  
  $pdo = new PDO("mysql:host=$host; dbname=$db_name", "$user", "$password");
  $con = mysqli_connect($host, $user, $password, $db_name);
$con->set_charset("utf8mb4");   
?>

i tried to add header(‘Content-Type: text/html; charset=utf-8’);
to the reg_query.php but it did not help