dcaconfig.php

<?php

/**
 * /system/modules/twoj_modul/dca/tl_iso_product.php (lub nawet /system/modules/dcaconfig.php)
 */

$GLOBALS['TL_DCA']['tl_iso_product']['config']['onload_callback'][] = function () {
    $user = \Contao\BackendUser::getInstance();
    
    if ($user->isAdmin) {
        return;
    }
    
    $GLOBALS['TL_DCA']['tl_iso_product']['list']['sorting']['filter'][] = ['author=?', $user->id]; 
};

$GLOBALS['TL_DCA']['tl_iso_product']['fields']['author'] = [
    'default'   => \Contao\BackendUser::getInstance()->id,
    'sql'       => "int(10) unsigned NOT NULL default '0'",
];