I think the story in SMT IV is good. It has a depth to it that makes you think. The world-building and the way the narrative unfolds are both impressive.
The 'aleph' in the short story often represents a point of infinite knowledge or a symbol of the all - encompassing. It can be seen as a doorway to understanding the vastness of existence.
The main themes in 'The Aleph and Other Stories' are quite diverse. There is a strong presence of the theme of the supernatural. The aleph is a supernatural element that challenges the characters' and readers' understanding of the world. There is also the theme of human nature. How people react to the extraordinary, whether with fear, wonder, or a combination of both, reveals a lot about human nature. Additionally, the stories often touch on the theme of memory and how it shapes our perception of reality.
There is the narrator in many of the stories. His perspective is crucial as he guides us through the strange events. Also, in the story of 'The Aleph' itself, Carlos Argentino Daneri is a notable character. He is the owner of the house where the aleph is supposedly located.