Migrate ABM federation from AzureAD to Google Workspace

Hello.

How we can migrate ABM federation from AzureAD to Google Workspace.

Now we have that solution:

Our general IDP - Okta.

Okta provision user accounts and passwords to Google Workspace and AzureAD(User account Password provision from Okta to another services).

Now we have enabled federation ABM with AzureAD(white squares on screenshot)

.

We want change federation method from ABM-AzureAD to ABM-GoogleWorkspace(yellow squares on screenshot).

Now we have this questions:

1. How change federation method from ABM-AzureAD to ABM-GoogleWorkspace.
2. Will already existing users be able to log in to apple services (for example, apple id / app store connect / Testflight) after switching federation from AzureAD to Google Workspace with an existing Okta password?
3. What problems can we face when switching ABM federation from AzureAD to Google Workspace.

Attached screenshot with our actually provision process(white squares) and future process(yellow squares)