Nether citadel hub for the roof of ...

Nether citadel hub for the roof of my nether base. I want this to have a center nether portal as the main point, and a medium-sized hole that leads to the bottom part of the nether through the bedrock. I want you to not overuse random blocks and keep the palette simple, but still have gradients and intricate details. This have areas to another room, like a highway. I want this to be absolutely massive and grand.