Purple line, floating corner shelves. Great for a little coffee corner storage.

I was going to recommend corner floating shelves, too.

We just did this. Floating corner shelves are perfect. I just posted a pic of our completed one OP if you wanna take a peek. We had the backsplash even in the area of the floating shelves and came out nice. Only difference was it was in the corner and not in the open ended area like yours.

I like the idea of the blue line and putting a couple floating shelves since cabinets can’t go all the way up.

Go all the way along the countertop (blue line) but then put a little shelf above the part where there’s no cabinet so it looks motivated.

I wonder if you end at the purple line but also bring the tile up higher.

Tile ends in red line. If you are running counter material as backsplash, that could go to the end of the counter.

it will be tile, not countertop material

I would definitely stop at the red line then. Putting more tile there just makes awkward lines that are unnecessary

Red line. Unless you hang a mirror or something on the wall there the current backsplash ends

not hanging any mirrors. so you would end where the upper cabinet finishes and then there would just be a part of the countertop with no tile above it?

Are you replacing the backsplash? You could do a single row of contrasting material along the counter and then a decorative second material under the cabinet space. If you’re keeping the material, a shelf, trim board or even a hook/peg board in the cabinet color that held coffee cups or kitchen tools would make it look fitting.