I have decided to align myself with phenomenology and say that an essence relies on a material universe and an observer. It is not fundamental in a reductive sense, but rather in a comprehensive and intuitive sense:
[W]hen a reference is made to a thing’s essence or idea, or when one details the constitution of an identical coherent thing by describing what one “really” sees as being only these sides and aspects, these surfaces, it does not mean that the thing is only and exclusively what is described here: The ultimate goal of these reductions is to understand how these different aspects are constituted into the actual thing as experienced by the person experiencing it. [Phenomenology]
Perhaps this will bring me too close to postmodernism, and I may have to veer away later. For certain, though, anything “essential” is not a Platonic ideal or an underlying, intangible reality. Rather, it is what someone perceives and communicates about reality.