Just as your physical body is only a vehicle, the astral body —whether solar or lunar— is only a vehicle. It is not the consciousness. Evolution and devolution is determined by the condition of the consciousness: if it is trapped in ego, then devolution is underway.
Acquiring a solar astral body provides an "anchor" in the superior worlds once the 108 lives are concluded, meaning that the consciousness might be able to continue some degree of work on themselves. But it is no guarantee against falling into klipoth.
Comprehension is known by observing oneself in the situations in our life that tempt or provoke the defect.
The door of repentance is always open, but the lower one falls the harder it is to enter.
"Do not worry; cultivate the habit of being happy." - Samael Aun Weor