This dungeon is a randomly generated structure that generates in a Jungle biome.
You can find a map leading to this dungeon in shipwreck chests(you will need it because the dungeon is very rare).
Fabric version of the mod marked as Realese(Fabric version reqiures Fabric API) and Forge as Beta, just for your comfort.
And finally there is a wiki, where you can find hints and solutions to all rooms.
Here are some screenshots:
Suggestions are very approved, write your ideas in the comments.
Why there is water inside the dungeon?:
There is a bug in the generation, when a room generates in the place where water is, all waterloggable blocks fill with water:
As I researched, it's a bug directly in the Minecraft generation, here is an issue link.
For now I don't know how to fix it.