Want to add floating shelf or something to put candles or small decorative items, and something for the floor

Wallpaper could help the room.

what about adding floor liner with modern design; and keep walls simple?

Install a tailored linen skirt on the wall sink (Etsy). I'm showing creamy white walls, natural wood shelves, natural fibre/bamboo roman shade, a washable mat or runner depending on the size of the room.

What about vinyl floor

Your floor seems to be in good condition, I would personally prefer to keep a ceramic/porcelain floor to replacing with vinyl.