Hello @Janus Bariñan ,
Thanks for reaching out.
You can only use the credentials of a user account that belongs to the managed domain as bind while connecting to Azure Active Directory Domain Services (AAD DS) and search over secure LDAP. More information : https://learn.microsoft.com/en-us/azure/active-directory-domain-services/tutorial-configure-ldaps#test-queries-to-the-managed-domain.
I would recommend you to post your idea in Azure Active Directory suggestions and feedback site. Thanks.
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