Secret cave biome

what if there was a skeleton cave biome that had skeletons and strays but there is a new kind of structure the grand skeleton cathedral and it has loot and tons of skeletons. Their would also be a new mechanic to hide yourself from skeletons wear chainmail but it only works in underground.just like piglin brutes only spawn in the bastion their would be a new enemy that only spawns in the cathedral called the undead knight a armored skeleton that kills you in 2 hits with his spear a new weapon only obtained looting the cathedral.the block this cave biome is made of is called shale. if you have any comments or ideas please let me know