Q:

ADFS 3.0 federated authentication in .NET Core 2

I am in need of a solution for using ADFS 3.0 identities in a ASP.NET Core 2 Web Api application.  The Windows Enterprise Support team at my organization has informed me that they are only familiar with SAML or WS-Fed based relying parties within ADFS, and are not interested in allowing me to help them configure OAuth, which I could consume directly within the application.  As far as I am aware, neither SAML nor WS-Fed are compatible with anything currently available targeting netcore or netstandard.
I've been looking at Identity Server 4, and it's so-called "Federation Gateway" functionality, but I can't find much in the way of documentation.  Is this something that could be useful for my use case?  I'm guessing that it's only set up to interface via OAuth or OpenID, but I could be wrong.
I've also looked at using Amazon Cognito as the middleman to issue JWTs based on the SAML response, but after I got a proof of concept working with this configuration, I realized the cost at $0.45/MAU is prohibitively high, as the application will have around 10-15k regular users.
If Identity Server isn't the solution, are there any other similar "Federation Gateway" type solutions available as preferably open source/free software?  Even if the solution wasn't .NET-based, I'd be interested in looking at it.  I'm toying with the idea of building something like this in Java or Ruby as a last resort.

A:

As of version 2.0, IDS4 can be a WS-Fed relying party. This would allow it to act as a middleman between ADFS and OIDC/OAuth RPs. 
This vid from the IDS4 guys covers the available options: https://vimeo.com/254635632
It's also worth noting that you can run ADFS 2016 servers in a 2008R2 or higher domain and that natively supports OpenID Connect but given what you've said about your internal "support" team, deploying IDS4 may be a better option, although probably more work. 

