Please, add a .zip or .7zip with the following content from the Telerik Reporting folder:
At the moment it's only possible to have your reports in old-fashioned projects.
It should be possible to add/design reports to SDK-style projects. That should work no matter what target framework is (.NET Core, .NET Standard or .NET Framework).
When using the Report Viewer under WinForms, Print Preview allows the user to scroll through all report documents. I.E., everything in the document map. However, when using the Wpf version you cannot. In the Wpf version, the user must use the Document map to select and scroll through each particular area. For large reports containing multiple documents, this is tedious. Please make the Print Preview functionality for the WPF control match that supported by the WinForms control.