In Hume's bundle theory objects/things are simply collections of properties and relationships. But properties may depend upon the observer. In relativity theory mass, color, length, and duration, for instance, depend upon the relative motion of the observer so different observers will not experience identical realities. Andrea Oldofredi also argues for this* in Rovelli's relational interpretation of quantum mechanics where "...the notion of an absolute, unique reality is abolished."
* See arXiv:2011.10295v2 23 Nov. 2020