Firstly there is no requirement for there to be anything that is a necessary entity (see my comment 134).
You came to this party a bit later than everyone else.
Let me spell it out. The necessary entity as far as the contingent universe is concerned is the final and full explanation for the contingent universe.
So if you say it’s energy then definitionally that is your offer of the necessary entity. But then, I can ask. Why a fixed amount of energy as suggested in the conservation of energy and why a certain amount of energy. I could also ask why does it start of maximally ordered. I could ask has it been around for ever and even , if it is the necessary entity.......How come Missus Higgins at the Duracell factory put it into tins. In other words if we examine energy it looks more like a contingent thing.
Why don’t birds get electrocuted on power lines but a giraffe, if it sticks it’s neck out sufficiently can electrocute itself on a tramline? Answer potential difference.