Apple Accelerate isn't a SIMD API, it's a higher level API that happens to use SIMD for its utilities. Apple makes great APIs, yes, I can't deny that.
You seem to have forgotten P/Invoke where your performance critical C++ code can actually be called from C#. You get your assembly and everything whenever you want, for a low initial cost of calling your FFI. And you also get a pretty damn good UWP experience, as well as WPF, WinForms and a long list of UI toolkits.
Let's be real for a second though, the Android NDK is an absolute joke , and calling the C++ experience on Android "great" might be pushing it a bit far.