Do not take the overhead cabinets into consideration.

Use a 4" mol backsplash or a backsplash to the window frame. Use the same material as the countertop to not draw the eye to the discrepancy of the cabs.

The splash would stop at the end of the counter. It looks like it could just clear the outlet. Or move the outlet.

Use a latex enamel paint everywhere else and it will clean up easily.

Here are the options. I removed the end cab for the rendering.

Splash to the window frame.

Splash with strip of paint under the window. Outlet in original position:

Without seeing the rest of the kitchen, I would be inclined to do as suggested by @tracefloyd on using same countertop for the short backsplash. If possible, relocate and repurpose the trash cabinet and have a nice stainless trash unit at the end there to break it up.