Calculate field - Quicksight

You can combine formatDate and substring to extract the relevant piece of information that you want.

formatDate(date, ['format']) https://docs.aws.amazon.com/quicksight/latest/user/formatDate-function.html

substring(expression, start, length) https://docs.aws.amazon.com/quicksight/latest/user/substring-function.html

If that doesn't work for any reason you can try extract to pull out only hours, minutes, and seconds then concat the fields together or use separate calculated fields.

extract(period, date) https://docs.aws.amazon.com/quicksight/latest/user/extract-function.html

I hope one of these solutions helps you.