Only thing from the content above i would change fundamentally, the part with the two door type features looks unusual, maybe remove one of those (see my edits above
) OR, the door shaoped feature could fill the entire wall, and then on top this circle, to make it distinct from a real door. Or maybe just the circle… and the background darker. And maybe some more attachments for the corridors …
This circle could shape could also be used as a sphere, for lights, hanging from the roofs. Also the center floor square could be extruded (see the Suntemple example main room with eh ocean view, also for the material) and on top featuring marble jars.