I have been to other realms and have observed myself in the invisible worlds - very difficult to do objectively.
It is my experience that the term soul, while bandied about without much if any description is considered through religious dogma to be permanent and complete. It is assumed to be complete without any evidence. My experience has shown me incomplete souls aka lightbodies. These lightbodies repeat life after life until they are completed.
Light coats the incomplete soul body until there are no leaks in it. Then choice on a higher dimension comes into play with regard to incarnation. Some "old souls" have completed lightbodies of a permanent nature. They have a soul. They can reincarnate or not. Those that reincarnate choose to come to work with humanity to imbue love in whatever form. Or they can move on as teachers in their "soul" group, move onto the 5D, 6D on up.
Both the lightbody on the way towards becoming a soul and the higher self interface with our physical bodies at different frequencies. The Higher Self does not leak light for example as the temporary light body. Light is made through love. The Higher Self dwells within our physical bodies and in higher frequencies. I have not been able to observe my HS whereas I have "seen" my lightbody - temporary soul. By this alone I deduce that they are different. However I am still investigating so that conclusion is not written in stone.
The Twelve have shown me that the HS accesses information as needed from the Akashic Records ranging from 6D to 4D. Higher dimensional frequencies have been downloaded, but I do not yet have the wisdom from experience to understand them.
I have tried to write about this on Medium and my views have been rejected and ignored. When you used the word quibble I felt my emotions bruised, and attachment that I have worked with but there was a miracle the Guides gave me regarding you.
That will have to be for another time if you want to hear about it. Maybe by email