Zulu Time Import Format

https://help.salesforce.com/s/articleView?id=000385167&type=1

'Date Time' field acceptable formats
YYYY-MM-DDThh:mm:ssZ

use custom formatting in Excel before the upload
don't forget to subtract 5 hours to get Zulu for central time
- use time() in Excel, example: =a2-time(5,0,0)
  - time() takes hour,min,sec as arguments