The ISO 8601 format is: YYYY-MM-DD. So value of 20230118000000 would become: 2023-01-18. The trailing six zeros are your time value. The zeros are simply there because there's not a specified time value with your data.
Normally the formatting of the time would go: YYYY-MM-DDT HH:MM:SSZ. And of course, the [-6:CST] is just your timezone.