Suppose you hold to the essence/existence ontology of Aviccena and like him believe that there is a fundamental entity which is essenceless existence, on which all entities that are composed of essence and existence depend, and conclude that such an entity must exist necessarily*, what else might you conclude about this entity?

I think you might be able to draw out the further entailement that this entity is perfect and be able to do so along the following lines:

1. There are entities that are combinations of essence and existence.
2. There can only be entities that are combinations of essence and existence, if there exists an essenceless fundamental entity.
3. An entity can only be imperfect in virtue of having an essence.
4. If (3), then an essenceless entity cannot be imperfect.
5. An entity must be either perfect or imperfect.
6. If (4) and (5), then an essenceless entity must be perfect.
7. Therefore, there exists an essenceless fundamental entity that is perfect. (conclusion, from 1-6)

* My admittedly limited understanding of Avicenna’s views is based on the following article: Ayşenur Ünügür Tabur, “The Relevance of Kant’s Objection to the Ontological Arguments and Avicenna’s Exploration of Existence as an Alternative Grouding,” European Journal of Analytic Philosophy 18:2 (2022): 5-27.