Can't use Windows Runtime APIs with .NETCore desktop app

I'm having troubles using the Windows Runtime APIs in my desktop app. I want to check package details in code and add Windows 10 notification cards.

I have the package Microsoft.Windows.SDK.Contracts installed, but my project can't seem to find it. It seems like it is not being added to the project's references, but my default package management format is set to PackageReference.

I have the Windows Application Packaging Project on this solution as well, with the TargetPlatformMinVersion as 10.0.18362.0 and TargetPlatformVersion as 0.0.19041.0, which works fine.

Is there something I need to do to the project to use the Runtime APIs?

I followed the Microsoft Docs, but it still does not seem to work.