I'm a 30-year ex-Windows developer - started with C/C++ briefly, moved to Java for a few years, and then to C#/.NET for about 23 years. Good riddance to Microsoft Windows. The keyboard shortcuts may be forever ingrained into my reflexes, but I'd rather use Linux or MacOS.
No concerns about .NET however. It's a cross-platform development framework and works well. It's also quite fast now.