Restricted domains sharing at site collection level - no longer an option?

Directions to configure domain-restricted sharing at the site collection level was outlined June 2018 at https://docs.microsoft.com/en-us/sharepoint/restricted-domains-sharing?redirectSourcePath=%252fen-us%252farticle%252fRestricted-Domains-Sharing-in-O365-SharePoint-Online-and-OneDrive-for-Business-5d7589cd-0997-4a00-a2ba-2320ec49c4e9

However as of today (May 2019) the options identified in step #4 of "To restrict domains in external sharing in SharePoint Online at the site collection level" aren't shown.  (The options for tenant/org level restrictions, however, are still available)

I opened a ticket with support, who was equally confused by the change, and her only conclusion was that perhaps the feature had been removed and now required a separate license.

Hoping someone can provide insight on this!

Thanks, 

JC