Shinji had already experienced the danger of lacking control, so he understood that he had to improve his strength step by step. He couldn't simply rely on mastering something or becoming the Ten-Tails Jinchuriki to gain power far beyond his own overnight.
The Ten-Tails in particular could be considered the most powerful force in the Shinobi World at present.
In his current state, Shinji hadn't even fully mastered his own Six Tomoe Rinnegan. If he tried to control the Ten-Tails now, the inevitable result would be an imbalance of power.
So before becoming the Ten-Tails Jinchuriki, Shinji had to get himself into the right condition.
From ordinary Jinchuriki, Shinji had reached one conclusion: only those who were strong enough themselves could hope to control a Tailed Beast and become a Perfect Jinchuriki.
That was true even of ordinary Tailed Beasts, let alone the Ten-Tails.
Shinji would only be able to control the Ten-Tails and use its power if he became strong enough to at least contend with it. Otherwise, he might repeat Madara Uchiha's mistake, be consumed by the Ten-Tails' power, and become nothing more than a tool for resurrecting Kaguya Otsutsuki.
The Overlord could descend at any moment, and the Akatsuki Organization could launch the final battle at any time. Shinji didn't have much time left to fully master his Six Tomoe Rinnegan.
He exhaled and carefully put away the Rinnegan and Red Dragon Eye he'd removed.
He wouldn't need the Rinnegan or Red Dragon Eye for a while, so rather than leave them in small nutrient tanks and let their Dojutsu slowly fade, he decided to return the eyes to Karin and Yakumo. They could nurture and develop them.
Just as Shinji hadn't fully mastered his own Six Tomoe Rinnegan, Karin and Yakumo hadn't fully mastered their respective