Custom UPN logins for Azure SSO

To allow custom UPN deployments with Azure SSO - all other 3rd party apps and services we use allow this and PHR is the only service that cannot do this. We won't be the only organisation with this type of setup.

For example, UPN address is username@domain.com but email is firstname.secondname@domain.com.

Workaround at the moment is to allow "sign in with Microsoft" social sign in which allows custom UPN logins (strange but ok) however the login experience is poor i.e. first login page - https://domain.peoplehr.accessacloud.com/Pages/User/Login.aspx > then user inputs email address > then user selects "sign in with different account" > then user selects "sign in with Microsoft".

Alternatively - perhaps to make the workaround better to use, to allow social sign in options on the first login so users click "sign in with Microsoft" straight away rather than clicking through many options/screens.