With respect to the feature "Push Logs to AWS S3 bucket " Atlas expect max-session-duration for IAM cross account role is : 43200 (12HRS) by default.
Some organizations like us have limitations on max-session. We reached out MongoDB Support, They said " The Atlas team has confirmed that currently, we do not support max session durations of less than 12 hours. However, there is an internal ticket for improvement, where session duration can be internally configurable via MongoDB's internal support UI. Case ref: 01276442

This will provide a flexibility for the organizations to have max-session configured according to their internal security policy.