She's a snail, still training in her shell. And when she's ready she'll leave like a butterfly from a cocoon, to become a slug. Only Naruto is worthy of such beautiful metaphors.
I remember them saying it would take all of Sakura and Tsunade's powers to summon like 30% of Katsuyu's full body, but then they never tried to summon her actual full body in the war which made that statement pointless since a higher volume of her was never even revealed lmao