Emrys got to know that one must form a Soul Space to become an Infinite Soul Master (King). Then, they must nurture the Soul Space with the help of their Soul Sea and evolve it into a Soul Universe. Once the Soul Universe fully forms, an Infinite Soul Master can advance to the Cosmic Star Realm, becoming a Cosmic Star Soul Master.
In this realm, cultivation progresses by forming one or more Soul Stars. Moreover, only forming Soul Stars is not enough. It is only the starting point.
A Soul Master must evolve their Soul Star into Soul Origin Realm.
If a Soul Master has only one Soul Star, it'll become a single Soul Origin Realm. However, if there are multiple Soul Stars, then each one must evolve into a Soul Origin Realm first. Only after that, they must fuse together, and ultimately, there can only be one giant Soul Origin Realm.
Now, the advantage of having more Soul Stars becomes transparent at this stage.