1. The Universe
The endless, expansive space wrapped around every celestial body that exists in the Living World. Along with the "Demon Realm," it is a single, large world in the Living World. In the world of Dragon Ball, the universe is located beneath the World Beyond, and it is hermetically sealed by a barrier that is engraved with a strange design. Within the universe, there are "nebulae" composed of innumerable stars, and there are "galaxies" composed of innumerable nebulae. There is a ruling Kami for each galaxy. Earth resides in the Solar System, a galactic nebula on the outskirts of the North Galaxy.
[Par.] A "Cosmic Police Organization" exists in the universe. However, they lack the fighting ability to oppose Freeza and the Saiyans. (Daizenshuu 4, Page 72)
Means each region of the universe, which is divided into East, West, South, North. It is expressed as the "East Area" and the "West Area." The areas divided into East, West, South, North are governed by respective Kaiou.
[Par.] Like the universe, the Demon Realm is also divided into multiple areas.
A gathering of local planets in the universe. Planets gather and form a nebula, and beyond that, a collection of gathered nebulae is called a galaxy. The four Kaiou who rule over the east, west, south, and north [sections] of the universe actually govern these galaxies. Because the Kami in the Heavenly Realm and the Kaiou supervise the galaxies that exist infinitely in all the universe, the sections known as the East, West, South, and North Galaxies are denominations that came into use through their duty.
I have bolded the part that implies more than 4 galaxies.
"Galaxies that exist infinitely" - meaning a lot of galaxies, effectively a large unknown number of galaxies in the Universe.
The last line pretty much answers are questions on the confusion.
"North Galaxies are denominations that came into use through their duty" - Meaning 'North Galaxy(ies)' is nothing more than a NAME or TITLE (Denomination), it does not mean literally 'a single galaxy in the North'.
So from this, I gather that Dragon Ball Universe indeed has MORE than 4 Galaxies.
Source: Daizenshuu 7 (World - View Terminology Explanations)