I don't think there's any reason why C# can't be comparable to C++, or any reason to think a programmer using C++ would be able to write significantly more effi

I don't think there's any reason why C# can't be comparable to C++, or any reason to think a programmer using C++ would be able to write significantly more efficient code than if they were using C#. We're not talking about Python here, C# is a JIT compiled language not an interpreted one. The performance could be roughly comparable given the same code.