“Would that be taboo to BS on top of BS?“

It’s your house, do what you like, but I call it the belt and suspenders look, and it’s a dead giveaway that its either a DIY, or that you didn’t have a kitchen designer. It’s such a beautiful space, it would be a bit of a shame to do that to it.

Is there a reason you don’t have cabinets there? You can put shelves in without tiling over your 6” splash. Or have built-in looking bookshelves built there.

Easiest option would be to paint the wall space and perhaps add large piece of art on the empty wall or a built in bookcase/shelves. beautiful space

Would keep the current backsplash as is and focus on liking a paint color for the painted walls, including above the backsplash and the blank wall between the windows and any shelving you add to the blank wall -- a splash of your favorite color. Then paint your island base cabinet the same color, leaving the rest of the cabinets as is.

What small and countertop appliances do you have -- microwave and toaster oven and blender/mixer -- could you build painted shelves specifically sized and to fit those, with space allowances for the heat producing appliances -- on the empty wall on the right?

Consider plantation shutters the same color as the window trim for your single window beside the overhead cabinets since that avoids having fabric near food prep (splashes) and it still keeps open the option to put a fabric window treatment on the larger window.

If you keep the current backsplash, the small piece, then you could just do something like this with a few wood shelves.

What is that end of room for? Island w stools if you really will use the stools is a nice angle to gaze at a good piece of art . Shelf would serve what purpose? You have tons of storage already . Seems like leave it alone till you know more . Get the stools and a light filtering shade for windows first.

If/when you buy stools for your island bar, make sure they're the comfortable kind or you're wasting your money. You might also look into a small round bar height table for between island and window -- then you could use the same stools for either place. You and your spouse could sit at the table by the window and the children could share the island bar.

If the more expensive fancier bar stools are not in your budget, do at least consider the mid priced wood saddle stools instead of the round flat uncomfortable kind of stools. If your family and guests have a place to sit, they'll not be walking around in your kitchen in your way.

With wood saddle bar stools, you can match the stools yet have different heights of stools. Being wood, the legs could be cut to be shortened as children get a lot taller.

https://www.google.com/search?client=firefox-b-1-d&q=wood+saddle+bar+stools

The wider stools will likely be the most comfortable. The heaver stools will likely be more sturdy. A smooth hole in the middle of the seat will not be felt-- it's for picking up the stools more comfortably with one hand.

You can get saddle bar stools with cushions attached or you could add our own cushions.

Some seats rotate.

Don't know how sturdy these are but a set of four with a bar/table would give you two for the bar/table and two for the island bar.

https://www.wayfair.com/furniture/pdp/andover-mills-bates-solid-wood-counter-bar-stool-w002316306.html?piid=1748887095#m8uuglff4z-5

If you choose a round top pedestal table, they'll likely be easier to move about as needed. Alternately, you might look for a table to set by your window to which you could add wheels that would raise height for your table or , cutting off part of the wood legs, could be the same height even with wheels added.