将php sql行记录插入隐藏表单输入值字段

I'm trying to insert sql ID record inside php echo form input value. Values that are inserted manualy via input field (by typing) are being displayed fine. Value inside input (named: potnik) is not being displayed. Is it ignored because is inside echo or is inserted wrong?

$sql3 = "
SELECT id, potnik_id, ura, naslov
FROM prevoznik 
ORDER BY HOUR(ura), MINUTE(ura) ASC;
";
$result = $conn->query($sql3);

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {

        //Spremenjena oblika datuma
        $date = date_create($row["ura"]);
        $ura_pobiranja = date_format($date,"H:i");
        echo "<div class=\"row list  divider-gray\">
                <div class=\"col-1 fs-09 fw-600\">" . $row["id"] . " </div>
                  <div class=\"col-3 flex-vcenter-items fw-600 fs-09\">" . $row["naslov"] . " </div>
                <div class=\"col-1 flex-vcenter-items fw-600 fs-09\">$ura_pobiranja</div>
            ";

        if ($row["naslov"] !== null) {
            echo " <div class=\"col-6 flex-vcenter-items fs-1\">Nastavi uro<form action='update.php?id=" . $row["id"] . "\"' method='POST'><input name=\"potnik\"  value='".$row["id"]."' type='hidden' /> <input class=\"form-control fancy-border\" type=\"text\" name=\"posodobljeni_cas\"/><input type='submit' value='Posodobi'>  </form></div>";
            echo " </div>";
        }
        else {
            echo " </div>";
        }

    }
} else {
    echo "<div class=\"col flex-vcenter-items fw-100 fs-1\"><i class=\"far fa-frown-open pr-3\"></i>Nimaš še nobenih opravil
                                    </div>";
}

Code that isn't working (hidden input field value):

echo " <form action='update.php?id=" . $row["id"] . "\"' method='POST'><input name=\"potnik\"  value='".$row["id"]."' type='hidden' /> <input class=\"form-control fancy-border\" type=\"text\" name=\"posodobljeni_cas\"/><input type='submit' value='Posodobi'>  </form></div>";

I had post parameters instead of get parameters set for update.php form action

update.php?id=

echo"Error on update ID:{$_GET['id']} POSODOBLJENI CAS:{$_POST['posodobljeni_cas']}";