Also note that Grpc.Core implementation of gRPC C# won't work on Windows ARM, since we don't provide windows-ARM flavor of the underlying grpc_csharp_ext.dll native library that Grpc.Core depends on.
Since Grpc.Core is currently in maintenance mode, we don't plan to work on this and you should treat Windows-ARM as unsupported in Grpc.Core.
You can try grpc-dotnet (which is now the recommended implementation of gRPC C#) - it doesn't have a native component and it should work even on Windows ARM.