> It's a wave, period, it's just that high-frequency waves can look like particle propagation if you squint, as seen in optics and acoustics

Based on the normal definitions of particle and wave, and based on things like the double-slit experiment, I think we'd have to conclude the behavior is closer to "neither" than to "wave".

If you define "wave" based on quantum behavior, then you're really just begging the question of what to call it.