Many other MDM's provide a list of variables that are accepted for app profiles/settings. I've not been able to find something similar for Sophos.
Thanks for reaching out to the Sophos Community Forum.
Let me know if the following page includes the information you were looking for. - Placeholders
If you scroll down to the key value pairs section of this article, you will see the info needs to configured outlook for ios.
Account setup in Outlook for iOS and Android using Basic authentication | Microsoft Learn