Maybe the same tiles all over the place ?? Often they stop at a specific height and are not used for the ceiling. The columns may have different ones or at least some “special” border at ther “feet”. Some other assets may also break the sameness.
So for now this look more like some of the backrooms… and for them it looks alomost too realistic 
I would also add some mold and dirt textures with alphas, usually at the intersection af different planes. Also the usual pool border that does not allow the exxcess water to be spread, stairs?
Try playing with the light. Give it distinct color and direction. Use more than one color. Sunlight is warm while the shadows in the same scene might catch blue from the sky. Consider what mood you want: do you prefer “high key” or “low key” lighting? Try several different lighting treatments of the same scene. Consider also the camera angle(s) and framing. Consider using more than one tile color on the walls – decorate (!) the place as an actual public architect might do. A mural, perhaps?
Your modeling, simple though it may be, is just fine now. (Many public spaces are simple.)
I would say lighting and the camera are a big factor here. Cycles is not a true ray trace renderer, so the ambient occlusion you get is not exactly accurate to real life. You may benefit from adding an ambient occlusion node onto your textures and playing with it (youtube it). Also the camera-- activate depth of field and slightly blur the background. Play with the camera settings to give a slight fish eye stretch around the outside edges like a real camera would do. Also adding dust particles to the air or a subtle volumetric fog can help in steamy situations.
To me, the lighting looks very white, and the bounces are too bright.
Try playing with the lights on a clay render, and then swap out the materials when you are happy.