Годная статья про нюансы реализации .NET Standard в различных версиях .NET.
https://weblog.west-wind.com/posts/2019/Feb/19/Using-NET-Standard-with-Full-Framework-NET
https://weblog.west-wind.com/posts/2019/Feb/19/Using-NET-Standard-with-Full-Framework-NET
West-Wind
Using .NET Standard with Full Framework .NET
Using .NET Standard on full .NET Framework is a mixed bag because the behavior of .NET Standard differs depending on which version of the Runtime you are integrating with. In this post I review what .NET Standard is and how it fits in with the full .NET Framework…