I'm using this on Windows, for an automated test.
The test runner is written in C# (.Net Framework 4.7.2), using Grpc.Core (e.g. the C++ wrapped as C#).
The application is in C++ using C++ grpc.
No secure channels, no special things, just local port, and no issues so far.
The only thing I've had to do is bump the max message size to 128mb, as big buffers are transferred (screenshots).
I only wish there was support for AF_UNIX (since it's now available on Windows), so I don't have to use a port, but no biggie.
Looking forward replacing it with the fully dotnet version (e.g. no C++ for C#), once we fully migrate.