There is no actual absence of Y. You are merely limiting existence in attempt to declare Y’s absence.
Y is a thing, Y is present. You perceive Y, you reference Y. X is a thing, X is present. You perceive X, you reference X.
Relative nothingness itself is a thing, a conceptual mechanism. You perceive it, you reference it.
Absence itself is a thing. A condition or circumstance. You perceive it, you reference it.
All of those are things; all of those instances concern thingness, not nothing, not nothingness. Even the concept of relative nothingness is a thing, a concept, which is perceived.
Nowhere in the equation is actual nothing or nothingness referenced.
If all there is is existence then existence is all things, not nothing (no thing).
It includes that very notion of “nothing” itself. As expressed, nonexistence or nothing is conceptual. It is abstraction, constructed in the mind and projected outward through concept and language.
Nothing, nothingness and nonexistence are conceptual mechanisms. Conceptual mechanisms employed by conscious beings, specifically advanced organisms like human beings, to help process information.
This has already been discussed on the other forum:
https://canzookia.com/viewtopic.php?p=654347#p654347
https://canzookia.com/viewtopic.php?p=784489#p784489
Distinction does not transcend existence as distinction always concerns existence. Every possible reference is to existence; even nonexistence itself is conceptual, a conceptual aspect of existence.
Existence is all, including any hierarchical apex.
Existence is all things.
Your statement in no way refutes the ontology. As expressed, existence includes paradox.