I think it would look amazing if you tile the entire wall area.

Are you taking out the existing? I would not do a backsplash. You don't need one, there is no sink or stove. The angle would drive me crazy as to where a backsplash would start and end

I wouldn't add more backsplash to that counter area (you already have the 4" one installed, and there is no need for one as you don't have a sink or stove on that wall.

Agree with adding nothing. Not a good look to add tile over an existing 4” backsplash.

A backsplash is needed behind a sink or cooktop because things splash up. The point is to protect your walls. You don't have either a sink or a cooktop there, and you don't need a backsplash.

Design-wise, it would not look good to stick one there anyway, which is why you are struggling with where it should end.

Agreed--I wouldn't do a backsplash at all on this wall. It adds too many complications with the angle of the staircase, and isn't needed given the use. I probably wouldn't even have done the 4" one you already have. We have a stretch like that (similar use) that I had intended to tile at some point...that was 13 years ago and we have never felt the need to have a backsplash there.

You have a backsplash. If you insist on tile remove the existing backsplash. However what is there looks good and is perfectly acceptable as is.

I would also shift the appliances over to the left and not under the cabinets.

Thank you all for your helpful comments. We have decided not to tile that side of the kitchen. Have a good day everyone.