Are you able to paint the focal color there too? It will highlight the cabinets below, no need to anything else.

Nice wall color!!!

Definitely not clutter up there... it looks like you have great windows/natural light beyond the peninsula opposite the oven wall... have you considered mirror or something to reflect and amplify the light?

If you have access to those same cabinets it would give you extra storage esp. for seasonal or seldom used items. Go to the ceiling with cabinets. That's wasted space more than a design feature.

I have worked with similar spaces above kitchen cabinets. I recommend keeping an interesting collection up there: pottery, baskets, vintage cookware, vintage coffeemakers/teapots...whatever you enjoy looking at design-wise. Here is my own example:

How much space is there if 12” I would put some cabinets with glass doors and light inside

I'd just leave it alone. Don't bring attention to it with putting things up there or paint / wallpaper. It's nice and simple as it is.