We actively monitor the issues coming in through the GitHub repository. You are welcome to register your bugs and feature suggestions there!
We are also present on chat.fhir.org on Zulip, on the dotnet stream, or for more general implementation questions, the implementers stream.
For broader discussions, there's a "FHIR on .NET" Google group.
If you're interested in a FHIR training, or want to know what other FHIR tools are available, please check here.