How does emptiness relate to the sense of Being?
Emptiness does not relate to Being. Emptiness is non-Being, Shunyata. First you find and identify with your Being, Existence. Then your being starts to hurt you until you surrender to your non-existence, non-Being. Only then true emptiness can be known, not before. Then finally you see that Being and non-Being are one. That’s enlightenment, The Absolute.
Finding your Being can feel like emptiness, since Being is empty of egoic identification, it has no attributes and nothing can be said about it. But it’s not true emptiness yet, and most people confuse it with enlightenment.
Sometimes non-Being is called “pure Being”. It is completely impersonal, transcendental awareness, not marked by any disturbances of the mind, including any emotions and relationships. It is complete aloneness. If you abide in the stillness of deep presence, observing your personality, emotions and relationships, it’s your Being. True emptiness is deep absence.
Similarly, mindfulness is Being. Enlightenment is no mind, mindlessness. There’s nothing to be mindful of in enlightenment, this term is no longer applicable.
There are levels of emptiness, and as you realize them all, your identity moves to “the next level”, so to speak, also ultimately illusory. Ego is empty, and once it’s realized, the identity moves to Being. Being is also empty, and once it’s realized, the identity moves to non-Being. But non-Being is also empty, and with that The Absolute is realized, which is ultimately also empty. The only thing that isn’t empty is the taste of an apple in your mouth. That is the only reality, the last layer of the dream, and thus your identity comes back to the body.