How Do I Check If Things Did Not Go Wrong On Any Line When Using mysqli AND INSERT?

Question

Which one is correct out of the following three that work fine in my inexperienced tests and why that one over the other two ?

Each code is different on the IFs that has this line:

echo 'INSERTING SUCESSFULLY: ' .mysqli_stmt_affected_rows($stmt);

<?php

mysqli_report(MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT);

$conn = mysqli_connect("localhost","root","","gulf"); //mysqli_connect("server","user","password","db");

$input_1 = 'mogambo'; //username.
$input_2 = 'admin@mogambo.com'; //email.

$sql = "INSERT into users (username,email) VALUES (?,?)";

if($stmt = mysqli_prepare($conn,$sql))
{
    mysqli_stmt_bind_param($stmt,"ss",$input_1,$input_2);
    mysqli_stmt_execute($stmt);
    
    if(mysqli_stmt_affected_rows($stmt))
    {
        echo 'INSERTING SUCESSFULLY: ' .mysqli_stmt_affected_rows($stmt);
    }
    else
    {
        echo 'Mysqli Error: ' .mysqli_error();
        echo '<br>';
        echo 'Mysqli Error No: ' .mysqli_errno();
        echo '<br>';
        die('Failed to INSERT!');
    }
}
else
{
    echo 'Mysqli Error: ' .mysqli_error();
    echo '<br>';
    echo 'Mysqli Error No: ' .mysqli_errno();
}

mysqli_stmt_close($stmt);
mysqli_close($conn);

?>

<?php

mysqli_report(MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT);

$conn = mysqli_connect("localhost","root","","gulf"); //mysqli_connect("server","user","password","db");

$input_1 = 'mogambo'; //username.
$input_2 = 'admin@mogambo.com'; //email.

$sql = "INSERT into users (username,email) VALUES (?,?)";

if($stmt = mysqli_prepare($conn,$sql))
{
    mysqli_stmt_bind_param($stmt,"ss",$input_1,$input_2);
    
    if(mysqli_stmt_execute($stmt))
    {
        echo 'INSERTING SUCESSFULLY: ' .mysqli_stmt_affected_rows($stmt);
    }
    else
    {
        echo 'Mysqli Error: ' .mysqli_error();
        echo '<br>';
        echo 'Mysqli Error No: ' .mysqli_errno();
        echo '<br>';
        die('Failed to INSERT!');
    }
}
else
{
    echo 'Mysqli Error: ' .mysqli_error();
    echo '<br>';
    echo 'Mysqli Error No: ' .mysqli_errno();
}

mysqli_stmt_close($stmt);
mysqli_close($conn);

?>

<?php

mysqli_report(MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT);

$conn = mysqli_connect("localhost","root","","gulf"); //mysqli_connect("server","user","password","db");

$input_1 = 'mogambo'; //username.
$input_2 = 'admin@mogambo.com'; //email.

$sql = "INSERT into users (username,email) VALUES (?,?)";

if($stmt = mysqli_prepare($conn,$sql))
{
    mysqli_stmt_bind_param($stmt,"ss",$input_1,$input_2);
    mysqli_stmt_execute($stmt);
    echo 'INSERTING SUCESSFULLY: ' .mysqli_stmt_affected_rows($stmt);
}
else
{
    echo 'Mysqli Error: ' .mysqli_error();
    echo '<br>';
    echo 'Mysqli Error No: ' .mysqli_errno();
}

mysqli_stmt_close($stmt);
mysqli_close($conn);

?>