He was taking such a significant risk, not to mention Little Ear and Purple Cloud, even if he was confident he could quickly achieve greater accomplishments in the Netherworld and even gain some control over the Reincarnation Power, he should avoid such a course of action; it was a last resort.
Moreover, whether Little Ear and Purple Cloud could successfully reincarnate was uncertain. If the people there were prepared and prevented the souls of Little Ear and Purple Cloud from escaping, it was not an impossibility.
Therefore, to prevent any accidents, he had to hurry there as soon as possible.
If his strength hadn't been lacking at the time, he wouldn't have entered the Netherworld and wasted these three or four days.
Regrettably, he entered the Netherworld too late, but who could have expected such a turn of events?