Apologies for the delay in responding to this post.
Difference between AIP Scanner vs Windows Server FCI - Refer to this https://learn.microsoft.com/en-us/azure/information-protection/faqs-classic#whats-the-difference-between-windows-server-fci-and-the-azure-information-protection-scanner
Is still supported by Microsoft on Windows Server FCI - Yes, it is supported,
Refer to these articles on how to deploy it
https://learn.microsoft.com/en-us/windows-server/identity/solution-guides/scenario--get-insight-into-your-data-by-using-classification
https://learn.microsoft.com/en-us/windows-server/identity/solution-guides/scenario--implement-retention-of-information-on-file-servers
https://learn.microsoft.com/en-us/windows-server/identity/solution-guides/deploy-automatic-file-classification--demonstration-steps-
Let me know if you have any questions.