Hi Barak,
Thank you for contacting Syncfusion support.
You can change the date time format value using GridDateTimeColumn.Pattern property, which contains the set of predefined date time patterns. For more details about setting the date time format in dataGrid, you can refer below link,
If you set the format for datetime column when AutoGenerateColumn property as true in dataGrid, you can refer the below link,
Please let us know if you have any other questions.
Regards,
Muthukumar K