If you’re trying to change product date time format and getting “Invalid input datetime format of value”, It looks bug of magento2. The field is a datetime, but the date picker set date without time.
One of the possible solutions is that to use Modifiers in Vendor\Module\etc\adminhtml\di.xml and then create the modifier itself in Vendor\Module\Ui\DataProvider\Product\Form\Modifier\Datetime.php. The modifier should set time config for your attribute.
Please refer for more info: Magento 2 Create Date with Time attribute for product