We really don't know exactly what it is that's "out there". All we know are the repeatable and predictable numerical values defined by our measurements. We define concepts that are consistent with these values, but they are clearly arbitrary. For example, you speak of particles and waves, supposedly real physical phenomena described by different mathematics and properties, yet both interpretations are valid (or at least, useful) under certain circumstances. Under others, they are totally contradictory.

No, I'm not saying there is no "reality", or that all knowledge is arbitrary. What I'm saying is that the nature of that reality (matter) is meaningless unless interpreted according to some conceptual framework (physics). And we know physics does change periodically. The last time was about a hundred years ago, and we're about due for another one.

The universe is much more a consequence of what we THINK it is than of any intrinsic nature or physical property it may or may not possess.