If the walls are smooth regarding plaster do you need any tiles at all?

If you don’t want to use white on the walls with grey unit fascias take a look at Wevet. A bright shade that looks more white until you see the ceiling join paintwork and then you can see the merest hint of grey. Looks nice in rooms that don’t get a lot of natural sunlight.

U can use white color tile but with grey tone in it according to ur discprition

You don't need tiles? Your colours sound very classic, leave it with white washable paint on walls behind units? I would only use tile if I needed colour/texture

Not without lots of photos. It's really hard to suggest colours without a bit of context. Is the floor slate or solid black?

the splashback has existing tiles to be removed so without replastering it would be simpler to replace with tiles. The walls are currently an off white but more towards the yellow spectrum. like the idea of an off white if it leans more towards the blue or grey side.

Evening is rolling in now so not the best lighting but here is a picture with all current contents.

wondering about something like these...