Infusing Byakugan into the Giant Tenseigan was undoubtedly the most effective and simplest way to restore it.
Hyuga Kagami did have Byakugan on hand, but only the pair seized from Hyuga Aoki. If he had ten or twenty pairs, integrating them into the Giant Tenseigan might produce considerable results.
But with only one pair, it was merely a drop in the bucket.
For Hyuga Kagami, rather than waste a pair of Byakugan for no meaningful gain, it would be better to save them for experiments. After all, Byakugan unrestrained by the Caged Bird Seal were currently even more valuable experimental material in the shinobi world than Sharingan.
As for the second method—using the Caged Bird Seal to draw Byakugan chakra from Hyuga clansmen—Hyuga Kagami was still somewhat undecided.
It was not that Hyuga Kagami was softhearted. He simply was not yet skilled enough at controlling the Giant Tenseigan.
He feared that once he activated this absorption state, the weakened Giant Tenseigan would desperately and frantically devour the Byakugan chakra of the Hyuga clan to replenish itself.
Moreover, there were only a few hundred members of the Hyuga Branch Family with the Caged Bird Seal engraved on their foreheads, and more than half of them were elderly, weak, women, or children with limited chakra reserves. If something went wrong, every member of the Hyuga Branch Family might die suddenly in an instant.
The Giant Tenseigan was both a supreme treasure and a profound curse!
The Otsutsuki Clan on the moon, reduced to a single remaining person, was the best example. Hyuga Kagami had to be especially cautious about this. He did not want a moment of carelessness to cause his fiancée, his disciple, and the rest of his clansmen to die needlessly.
Besides those two simplest methods, there was another way