You are fallaciously conflating a mathematical model with your own personal metaphysical interpretation of what the model represents. You are presupposing that a purely mathematical description in terms of a superposition of basis states literally represents, in ontological reality, particles being in multiple states at once, and then when I say I disagree with that metaphysical accounting, you accuse me of denying the physics.

But I am not. I am denying your philosophical accounting of the physics. Nothing about a superposition of basis states implies that particles are in multiple states at once. Do not conflate a mathematical description (superposition) with a specific metaphysical ontology, and don't accuse others of being science deniers because they disagree with your metaphysics. I do not appreciate that at all.

We also use superposition of basis states in classical statistics as well, and no one in their right mind interprets that as the particle being in multiple states at once. The only thing that makes quantum theory different is that we also have to keep track of a phase, but the phase is mathematically decomposable into a function over its statistical history, and is thus merely a sufficient statistic over the particle's historical statistical trajectory. The whole theory is mathematically equivalent to a statistical theory with history dependence.