Help - SSO Authentication doesn't populate fields in response from platform (iOS, Google)

The sign in flows all work fine but the issue is the response I get doesn't map to the fields correctly in my Users Collection, so for example:

Google writes a users FirstName & LastName to DisplayName

Apple says it will share name but nothing populates again the user collection displayName.

Does anyone know where I can check the mapping and ensure the responses point correctly to the fields in Firebase?

Otherwise I need to modify my sign up to allow for instances where the data isn't populated correctly from the Authentication platform which will be a bit messy and cumbersome plus not a great UX if they used SSO and need to then provide info the platform already had.

Thanks,

Helena