Event::on(
Pdfs::class,
Pdfs::EVENT_MODIFY_RENDER_OPTIONS,
function(PdfRenderOptionsEvent $event) {
// Use Craft's designated temporary path, which is writable on Craft Cloud
$cloudTempPath = Craft::$app->getPath()->getTempPath();
$dompdfTempDir = $cloudTempPath . DIRECTORY_SEPARATOR . 'dompdf_temp';
$dompdfFontCacheDir = $cloudTempPath . DIRECTORY_SEPARATOR . 'dompdf_font_cache';

try {
FileHelper::createDirectory($dompdfTempDir);
FileHelper::createDirectory($dompdfFontCacheDir);
} catch (\yii\base\ErrorException $e) {
Craft::error("Could not create Dompdf temp/cache directories: " . $e->getMessage(), __METHOD__);
return; // Stop further processing in this listener
}

$event->options->setTempDir($dompdfTempDir);
$event->options->setFontCache($dompdfFontCacheDir);
$event->options->setFontDir($dompdfFontCacheDir);

// Set other helpful Dompdf options using setters
$event->options->setIsRemoteEnabled(true);
$event->options->setDefaultFont('sans-serif');
}
);