Going straight to beat Kaguya up was far too unrealistic; this really wasn't something that could be resolved in a short time.
Hui would never allow the Infinite Tsukuyomi to come to fruition, so there was one and only one way for them to release Kaguya—undo the Planetary Devastation sealing formula on the moon.
Simply put, they had to blow up the moon!
This was no small matter. Setting aside the question of how to accomplish it, the moon's disappearance alone would have a huge impact on the entire planet. If he really destroyed the moon in a fit of hotheadedness, Hui would be kept busy with the aftermath.
Besides, he still had to ask the nameless old man on the moon for his opinion.
In any case, this wasn't something that could be done in the next few...