Things like bottlenecks, during the Qi Condensation Stage and Foundation Establishment Realm, mainly manifested when, in the process of absorbing spiritual power, the total amount of spiritual power reached the dantian's maximum current capacity.
To continue cultivating, one had to expand the dantian's capacity before advancing to the next realm.
There were methods to follow and traces to seek when it came to expanding the dantian and breaking through bottlenecks.
However, from the Core Formation stage onward, cultivators formed magical power imprints and condensed Golden Cores. Although these still remained within the dantian, all magical power was stored within the Golden Core.
At this point, as magical power grew stronger, the Golden Core became increasingly condensed, and its magical power reserves rose in tandem until they reached the upper limit of the current realm.
Thus, there was no longer any need to further expand the dantian. At most, one only needed to strengthen its resilience and durability.
The situation after the Nascent Soul Realm was much the same.
As for this realm's upper limit, it was the state where the intensity of one's magical power could advance no further.
At that point, cultivators would vaguely sense the existence of a barrier within their minds. This was the new bottleneck.
Compared to the tangible path one could follow at the beginning, bottlenecks at this stage had become elusive conceptual existences.
To break free from them, cultivators needed to perfect themselves as much as possible and accumulate enough strength to continue climbing.
Only then would they have a chance to shatter them within their minds, triggering a transformation in the intensity of their magical power and raising its upper limit.
So-called self-perfection meant fulfilling certain conditions.
For example, condensing a true spirit before advancing to Spirit Transformation, mastering a Dao Track Projection