I haven't seen anything about it.
No. What sort of support are you looking for?
Displaying them from a file. Have it listed on this page as a supported format.
Add raster data—ArcGIS Runtime SDK for .NET | ArcGIS for Developers
GeoPDF isn't my personal choice. I personally think it is a crummy format.
But organizations such as the USGS publish GeoPDFs, so users ask about them.
I'm not really following. You want PDF to be a layer type to embed with the other layers in the MapView?
PDF is used for publishing/sharing documents, so it would make sense to be able to generate GeoPDF from a map to share, but I don't really see how this could work as a layer in the map.
The link you pointed to doesn't show PDF as supported. PDF isn't a raster format either, so wouldn't belong there in any case.
Scenario is user says "Hey, I have this GeoPDF I got from the USGS. Can I display that in your app?" (doesn't care about implementation details).
I think I need to say "No". Am I correct?
I think I could also say. " . . . but maybe if you can get it in Geotiff." (cause Geotiff appears to be a supported raster format). Correct?
Yeah pretty much. It's kind of like saying: "I have a PDF... can I add that to my Word document?" vs. "I have some text and images, can I add that to my Word document?"
So yes, GeoTiff should work.
But does Geotiff work if I don't have a Standard license or above?
That makes a difference. My customers are consumers, not professionals. They would not be paying for a Standard license.