My non-physicist but curious-about-the-topic take is similar. Things at the quantum level are not "complex" in the systems-theory sense. They couldn't be, I think, since we're dealing with the most basic constituents of the universe. They are mysterious, confusing, wildly counterintuitive... but they are fundamental. The most basic stuff there is.

The study of these things, on the other hand, is genuinely complex and difficult. But that's epistemology, not ontology.