If someone wanted to reach the Primordial Taiji Golden Immortal, Chaos Realm, or Heavenly Dao Realm in the future, they would have to leave the Heavenly Dao's ranks. Before doing so, they would have to repay all the karma they owed. Otherwise, the Heavenly Dao Laws would bind them and prevent their breakthrough.
The Heavenly Dao Saint Position brought both authority and responsibility. Its holder had to work for the Primordial World: put its laws in order, resist foreign enemies, repair the world when problems arose, and carry out tasks assigned by the Primordial World's Heavenly Dao. Until they had repaid all their karma, they could not relinquish the position and regain their freedom.
Of course, becoming a Heavenly Dao Saint had drawbacks, but they were not too severe. The benefits were greater.
For example, after becoming a Sage, one could use the Heavenly Dao's authority to lift the restrictions imposed by the world's laws. Without repaying one's karma to the world, one could fully merge one's Innate Imperishable True Spirit, Primordial Dao Fruit, and Hunyuan Ancestral Qi, thereby attaining the Hunyuan Great Firmament Golden Immortal realm.
That would save the immense time needed to accumulate Merit and repay one's karma to the world. And after attaining the Hunyuan Great Firmament Golden Immortal realm? A Hunyuan Great Firmament Golden Immortal could earn Merit far faster than a Half-Step Hunyuan Great Firmament Golden Immortal, and comprehend the Dao and cultivate much more efficiently.
For example, after becoming a Sage, even if someone was utterly slain, their imperishable primordial spirit destroyed and every trace of them erased, they could quickly revive through the Heavenly Dao. They would not have to return to the Great Dao and lie dormant for countless ages.
Of course, a swift revival through the Heavenly Dao would not