Render is fabulous!
I’m not quite sure what that is below the mirrors though.
It looks like a washtrough in concrete, but it looks kind of silly because you just can’t build that in concrete in that form with those dimensions. You also can’t get corners that sharp. Even if you try, they break off when the formwork is removed.
You can’t fix the taps in that configuration, you can’t build the washtrough, it’s not deep enough, and if it’s one piece, you can’t get it into the room, you can’t repair the pipes - you get the idea...
Lovely ideas, but very impractical. Have a look at John Pawson or Claudio Silvestrin’s work for inspiration for stuff like this. They make it work though