The latter is correct and will determine the value of any proposed work you might think of to reach out to other soul components. The deep subconscious is a product of the physical makeup of the human when incarnated and as such, this is Earth realm business, and like everything that happens within the earth plane, comes into play when that soul extension is present in the physical realm or perhaps as a discarnate spirit on its way back to the light if it becomes waylaid for a time and earthbound.
Once in the light, there is no further healing done on the light beings directly. That is why doing as much work while in the physical is important to pave the way for a better future with a return eventually in a new incarnation by that portion of the soul. This will create many blessings, to do healing now, because all of the future will be enhanced as a consequence. It is not feasible to go into the light and work on other parts of the soul with this process because those portions of the soul will not have the same makeup while in the light—the defective portion will not be present—that is shed and left behind with the death of the body. The soul experiencing, to cause difficulty as a result of the corruption creating the disconnect of the deep subconscious, will live on within the akashic records as a problem in whatever it has caused to happen, but that as well will be an influence energetically only on the earth plane, and for the soul extension when present in the earth plane, and other soul extensions experiencing life that are connected and influenceable by earth plane akashic records in lifetimes in parallel through the crosstalk that happens. So it is not feasible to do what the first part of your question was asking about, to carry out sessions on parts of the soul within the light.