What AWS config file settings are honored?

[Elastic noob warning!]

Fundamentally, I'm trying to figure out how to automatically update temporary credentials for the Elastic AWS integration.

I'm trying to configure my AWS Elastic Agent integration to use a shared credential file. I was hoping to use the credentials_process setting but it doesn't appear to be working. I'm wondering now if the the only things I can usefully put in that file (for the purposes of the Elastic AWS integration) is

access_key_id = ...
secret_access_key = ...
session_token = ...

Are any of the other AWS config settings useful in this context?

Do people have other suggestions for dealing with the problem of updating temporary credentials?