Hi,
Welcome to the community!
To be clear, you’re moving from Okta SAML to Azure SAML, right?
If that’s correct, then based on this guide, you shouldn’t need to do a back-end migration of identity_provider since it will be saml either way.
On the other hand
This part is very relevant, indeed. I’m not seeing a way to update a user’s login. How different will it be? Is it maybe just a matter of case? E.g. ann.campbell@… vs Ann.Campbell@…?
Ann