I am guessing that you want some kind of separation between dining room and kitchen? You want to keep steam and any oil in the air, from cooking, out of the dining room, stopping it at the ceiling with a wall but keeping the dining room open so the light from the large kitchen window can filter into the dining space? If I am right, the shape of an arch would best match the architecture of your house or of these rooms. An arch is an architectural element as well as a design element. It is possible though that an arch will be totally out of place in your space when a cleaned lined separation would look very nice. Hard to tell. Can you post a picture or give some verbal detail about the style of your spaces?

Is the tile for the flooring? I would recommend long rectangular plank tiles, there are many different looks available here is an example of one project we did that gave the client a neutral design option, they are tiles that look like a textured wood.

Merino/Green/Century Laminates in that order.

quartz corean white synthetic marble any one as per your budget