Yes, energy has necessarily always existed. And due to the vast infinite size of the universe, everything that exists at any one moment also exists, within only an infinitesimal error of duplication, elsewhere in the universe. Literally every person has an infinite number of duplicates throughout the universe, although each is only a duplicate for an infinitesimal moment before diverging into someone slightly different. So yes, everything that now exists, has always existed … somewhere, just not on Earth.
Energy, or better phrased, “Affectance” is the ONLY fundamental physical existence.
Different people have their own definition of “God” … a great many and greatly varied definitions. But to be scripturally precise, no, God is not the energy itself, but rather that eternal cause of it of it being there.
You also have to question the applicability of concepts such as causality and existence to concepts such as energy.
It’s easy to ask questions and expect that everything conforms to your standard way of thinking, namely, that everything can be said to exist or not to exist and that everything has causes.
God is the creator of the universe. He is the cause of the structure that we experience.
I don’t know what He is made of. I don’t know where He came from. I don’t know if He always existed.
I think that those kinds of questions are beyond my understanding. I could make up a story about it, but would it be anything more than a comforting fairy tale?