Before deciding on a colour, don't forget to consider your kitchen cabinetry, benchtop, splashback, etc (and dining furniture)... for example, if you have a classic hamptons (farmer style) kitchen (and furniture) then don't discount a warm white for the walls... it won't look clinical as the warmth will come from the kitchen cabinetry, etc and dining furniture, e.g. But if you have a "hamptons inspired" look with a slightly more contemporary kitchen cabinetry (and furniture), then in my opinion (all nice options above but a bit too beige'ish for me) so I would suggest a light shade of a warm grey e.g. Whichever way you decide to go, try to narrow it down to 2-3 colours, get the small pot samples and paint each one on all the applicable walls as they will all look different at different angles depending on how they reflect natural daylight and the lights at night time... then you may be able to make a clearer decision. Good luck! :)

I work as a colourist and the easiest method for a upmarket look is to choose an exact colour to match one of the colours in the tile. I would take the tile to a paint shop and get the colourist it match exactly one of the greys in the tile. Make the depth of the colour a light version. All white walls are on the way out. Lappatto tiles usually have some texture as they are semi polished. This is the latest look in tiles as they give a shine without the maintenance of polished porcelain which had been in. They are usually less slippery than satin or polished tiles depending on the brand.

Suggestions from neutral colours: https://www.dulux.com.au/colour/colour-trends/2018/essential Ceiling & walls the same colour is a good choice for square set. There will be subtle hue difference in various lighting situations anyway, which provides depth and makes for an interesting look.

This is a very personal choice as dreamer mentioned. You can order tile samples from tile cloud or TileMall for $15 for 5. Pick some options you like and put up in the kitchen next to the other elements. You will soon know which one you love the most 👍🏻