Our apologize for the late handling of this issue. We have looked at the problem and the TargetFrameworkVersion is actually not used in the end by either Rider or VS because they are both referencing System assemblies provided by Unity, so the .NET Standard 2.0 version is implicted by the usage of these assemblies. If you encounter specific problem with Rdier about this, you can report the issue directly through Rider IDE. Thank you.