[mlhpdx]

The implementation isn’t using any modern C# features?

[neonsunset]

Unfortunately it doesn't. The newest and hottest way to do this is to either use bespoke matmul from System.Numerics.Tensors or at least using Vector<T> for SIMD (which is trivial and not "the last mile" optimization it often seems to be).

[akashcoach]

Which modern features do you mean? Java and C# code looks similar to me.