You can use class in your column field in your ui_component
XML file like below..
In your case, you can override your sales_order_grid.xml
in your custom module or custom theme and you can change column class for date.
<column name="date" class="Vendor\Module\Ui\Component\Listing\Column\Date">
<argument name="data" xsi:type="array">
<item name="config" xsi:type="array">
<item name="filter" xsi:type="string">text</item>
<item name="label" xsi:type="string" translate="true">Date</item>
</item>
</argument>
</column>
And then you need to create UI component class for it. You can create that on below path..
app/code/Vendor/Module/Ui/Component/Listing/Column/Date.php
Content for this file is ..
<?php
namespace Vendor\Module\Ui\Component\Listing\Column;
use Magento\Ui\Component\Listing\Columns\Column;
class Date extends Column
{
public function prepareDataSource(array $dataSource)
{
if (isset($dataSource['data']['items'])) {
foreach ($dataSource['data']['items'] as & $item) {
if ($this->getData('name') == 'date') {
$item[$this->getData('name')] = date("d.m.Y H:i:s")." Uhr";
}
}
}
return $dataSource;
}
}
Output :

Hope this will help you!