The NuGet packages don't differ .Net Core projects from .Net Core with Desktop Compatibility Pack. This leads to incorrect resolving of the dependencies and the .Net Core projects targeting .Net Core 3.0 cannot be built.
Workaround: An option applicable for all the libraries is to extract the assemblies from the .nupkg files. For PdfProcessing and ZipLibrary you can use the assemblies directly from the pdfviewer installation folder.