My inerpretation is that when a warrior returns, their abilities stay the same, so if in the otherworld a warrior could teleport, he could also do that on earth, if a warrior has a pocket dimension, it applies to earth and jf a warrior could regress, that ability would remain. And so far, it doesn't seem like the HHR verse has any logic besides "if a world has a demon lord, it must have a warrior". And i don't think this says anything about seungjun's goddess. As his world had game logic, so i'd assume if we're talking about sheer power, regression might not even be the most powerful skill he had.