Adaptive scopes configure Microsoft 365 retention policies so that the policies automatically apply to mailboxes that come within the scope of a query against Azure AD. A limited set of Azure AD properties are available to query and domain name isn't one of them. This article explains how to store the domain names for user accounts in a way that adaptive scopes can use them to identify target accounts for a Microsoft 365 retention policy.
https://practical365.com/adaptive-scope-domain-name/
