Filler will help a lot.

I would have moved the switch or skipped the backsplash but what’s done is done. Once you get moved in you won’t notice it as much

It is salvageable. MOVE the switches now. I had my electrician return and re install all the switches when I realized that they wouldn’t allow my tile to fit properly ANYWHERE on my backsplash.

The cabinets being too deep is only part of it. It doesn't look connected to the rest of the home, because the color tones do not match the beautiful trim, and clash with the floors. The blue and the pattern of the splash is out of left field. It's a great pattern, but without a significant amount of blue elsewhere to connect it, it feels very lost and arbitrary.

I have no idea what this is for at all. As for the backsplash you cut the tile to go around the switches and take the backspalsh up to the bottom of the wall cabinet. I reallty need to see what the rest of the space looks like . Post pics here in a comment DO NOT start another post.

Thank you for all your comments. I have included other photos for more context. We live in a 1915 house with shellac on heart pine wood which we have retained for our kitchen with original oak floors. It’s a combo of woods for sure. Re Depth: We will have a fish tank there so I was designed for that. We will have a blue fridge. We were thinking that the backsplash would go all the way up. However looking at the plans again we realize that the design was not including backsplash on this cabinet are at all! Skipping the backsplash and moving everything back flush to the wall might solve the problem. However we have already installed the countertop here. (We will have a blue 4-door fridge Bespoke by Samsung. Photo is from showroom—not our fridge which will be all blue.) thoughts? Will skipping the backsplash, adding the filler and not moving the cabinets solve the problem ?

*We will have a fish tank there so “it” (not “I”) was designed for that.

Your original question was "what to do to make it less wonky." There were ways to make it less wonky.

But making it look good: I would start over. Take out cabinet and move to left, Move outlets. Counter needs to sit up to or behind wall. Tile.

Always have a total plan before starting. Otherwise, this is what happens.

You'll have a fish tank there? I think it is an odd place for one and then negates the backsplash.

You can buy a blue fridge if

1) You will never tire of it

2) You will tire of it, but have the funds to replace it when you tire of it.

3) You aren't planning on selling before the frig dies.

ditto with tile

Agree to undo that filler, go back to the left-flush option, reseat the counter and deal with the switches. Also the switches are going behind a tank, if I understand -- is this really a good plan to have access to them?

I can see that you are into fun finishes, but also if it is not too late I would like to advocate against using that tile in your 1915 house :) The tile and other finishing touches can be something that bridges the gap between the house and the modern kitchen. there are other options that are MCM but less agressively mod/atomic age.