Does the "I" get unified with the Totality in the end?
No. There is no “I”. Literally. This is not a play on words.
Something that does not exist cannot be united with something else any more than it can be separated from it. All there is is Pure Consciousness.
What we call “I” is a concept that appears or manifests in Pure Consciousness. As a concept it was never separate from Consciousness. So, the idea that it can unify with something is false. At best it is a crutch along the path.
Realization of Truth or Spirit is the cessation of the belief that we are exclusively an entity. In other words, we imagine what we are not and identify exclusively with that image, then that exclusive identification ceases and What We Are is realized.
All that changes is that something in the mind is removed. Consciousness is never achieved. The pursuit of Consciousness is a mental trap that many, many spiritual workers keep repeating without stopping to ask the deep questions: who am I? Where is “I”? What is there? What “is”?
There is only Pure Consciousness and the appearance of multiplicity. In the sense that many things appear and many things are experienced. One of those many things is the concept “I”, and the body and personality associated with it.