Stimulosft Reports.WPF works on .NET 6/8. You can find samples for .NET 6 on Github.

Some time ago there was no support for the Roslyn compilation in .NET Core. But for now, the compilation mode works in .NET 6 as well. The Compile() method does not throw the PlatformNotSupportedException exception anymore.

Check that you are using the latest version of Stimulsoft assemblies.