My bad, he needs to produce a Sumatra Gold from his Mystic Zinger heart specifically, in order to complete Dhya's race change. Which would be a 2 year long endeavour, based on the time that has elapsed during that chapters we had with Inala, he'll likely need another year or so to complete it.
What's funny is that Yarsha consider's him a calamity based on the data they have on his previous endgame build ( Spawning Zingers army, stealing prana & life force ).
They don't know the full capabilities of Perfect Biome Domination,
Plus he hasn't even gotten a tertiary nature.