I suggest you add: Chaotic Neon(Harder biome) and Industrial Candoria to Fire Element worlds from U8 to U10.

I suggest you add Permafrost in north and south of the map in Water and Air element worlds.

I suggest you add Forbidden Spire to Air Element world.

I suggest you add a dragon comparable to Flakbeard in both air and fire element worlds.

I suggest you go along with the Candoria Takeover scenario I suggested and add 3 other overlords that can appear in each elementary worlds.

I suggest you add volcanic islands and jurassic islands to water element worlds.

On top of Candoria overlord, a Jurassic overlord should be in Water Element world. A Forbidden Spire overlord, in Air element world. And a Neon overlord in Fire Element world. The biome has to remind of those Terminator movies.

Candoria overlord should be in Geode topside with its own new alien biomes.

As Candoria Overlord has candycoated part of geode Topside, he's part-alien, and he has very solid attacks. Indeed, the battle starts in a small room, but candy overlord uses telekinesis and lifts blocks in the room, until the room is full size and doesn't have breakable blocks anymore. Lifting and throwing the blocks to players. Blocks that doesn'T hit player stacks to the nearest solid surface.

There should be multiple materials, freezing ice that causes damages cold burns, burning iron that puts player on fire, Solid neon cubes that takes away more ER than regular neon water, Sea salt blocks that and chocolate that slows down. Dry saltwater cubes could reduce all % stats.
The Candoria Overlord would turn spots of the floor into X Y Z or none so players would have to find a safe spot on the floor to rest on and carry the boss to.
When X Y Z part of the floor is fully cooked by the Candoria Overlord's telecookingnesis, that's when it lifts up and is thrown at players.

The whole plot would be that Candoria Overlord is candy-coating Geode and other adventure worlds in order to produce an industrious amount of pastries and candies. Hence, the Industrial Candoria biome in Fire element U10 world.

Defeating the Candoria Overlord would be quite a challenge.