You are actually asking about the essence of an entity. It is a very difficult question. What is actually being a given being? Will you be someone else when you change your hair colour? And if you go through a mental breakdown or experience enlightenment? And will you be a different being in 30, 50 or 70 years? Were you a different being in your childhood?Is the human freq band of perception related to our physical equipment, biochemical processes or something else? Is “being“ related to that equipment or to consciousness? Or both? Certainly if you take a drug or get hooked up to some electrodes or go into some meditative trance, that can alter the band of perception. That may even add new experiences and perspectives on being Even if only temporarily. State of being and band of perception are certainly bi-directionally inter-related but I don’t think that if you alter one, you destroy the other.
There are two philosophical positions, such as perdurantism and endurantism, but this is some kind of a matter of chosen discourse. You can read about them, among others. here: Temporal Parts (Stanford Encyclopedia of Philosophy)
However, I do not know the answer to the question about the essence of the being. However, if anything was to be indestructible, maybe this is it? And what is physical is perhaps only a kind of representation of what is under the visible surface.