Struggling with Materials (among other things)

Hello good people!

I started rendering a few months ago, but not doing it as often as I should have, so this is shamefully my 10th render and yes, I need a lot of help. I’m not satisfied with… well almost anything and feeling deeply overwhelmed with tons of tutorials and information.
Currently, I’m in a process of making a bathroom. I started modeling everything in white color in SketchUp, and decided to add color/ materials later in Vray. I don’t know if that’s a good way?
My issue here is that I would like to get both moderate roughness and very subtle glossiness on these tiles.
I added pbr textures. When I load all of them (linear): AO, roughness, normal map and displacement, the result is this extremely rough texture, and it’s very bad in this particular room. When I don’t load any pbr map, and adjust only glossiness in vray, the result is no texture at all.
I know this isn’t a good level of rendering, so whatever can be suggested how to improve my render beside this tile problem, I would be very very grateful.