A quantum ensemble is not "dualistic". It is "non-dualistic". It is both/and, not either/or.
And has nothing to do with "simultaneity". Indeterminacy only states the irreducibilty of the wave to the particle and vice versa.
The ensemble is diachronic not synchronic. It's time-centered, not timeless.
Even within so-called "quantum ensemble" interpretation, EM is both a particle & wave. Can you explain to me how energy being two very different things at the same time (or at different times, to explain away how EM travels without media) is not dualistic?