I used Carlos and hobbykings design to fix the issues of the ancient guardian design.

The ancient guardian was previously an elder guardian who dwelled within the ocean monument where the story of the Hidden Depths DLC unfolds. After the shattering of the orb of dominance, one of it’s shards landed within the hidden depths of a deep ocean. Sometime after, an elder guardian discovered the shard and unwillingly become corrupted by it. The shard rapidly transformed the elder guardian and began to spread it’s corruption to a nearby ravine, enraging the ocean currents. At the time that the heroes begin to descend the ocean depths, the corruption of the ancient guardian begins spreading throughout a coral reef known as Coral Rise, wreaking havoc on the nearby small islands.

Upon reaching the end of the lower monument, the ancient guardian is seen destroying it’s own lair to challenge the heroes who entered the chamber. After an intense battle, they manage to defeat the ancient guardian, calming the ocean currents.

More facts here: https://minecraft.fandom.com/wiki/Minecraft_Dungeons:Ancient_Guardian