You didn't ask about the table, but it looks quite nice with the stain as-is. I would be surprised if you couldn't sell that on craigslist for decent cash and buy an already-painted table or a table that far more deserves painting for way less money and effort than it would cost to properly refinish a table like that.

I also think your kitchen already looks pretty as-is and would just go with a backsplash that is the same color the wall already is if the goal is a pretty kitchen for resale.

Given that you have a bunch of nice stained things that you want to paint, I'm getting the overall sense that stained wood just isn't your jam. Which is fine (totally fine!), but it probably clouds your judgment as to what is nice stained wood and what isn't. This is like that time my mother asked me to taste the liver and onions she just made and tell her if it needed more salt. I cannot begin to express how little I can distinguish that dish from any other version of it with all possible levels of salt because liver and onions is so overwhelmingly disgusting at every level of salt.

I think that's where you are with all the stained wood items in your house, so you are going to have to take our word for it that the kitchen already looks pretty. It definitely does. If you're just going to sell it, save yourself some money and effort because the kitchen already looks nice.

However, if you do stay, definitely don't sit around eating liver and onions just because we say it's good. Do whatever makes you happy.

However, I have a suggestion as you go about that. What you have right now is a stained wood floor with stained wood kitchen cabinets and a stained wood table and chairs and a stained wood built-in and stained wood stools all right next to each other. Even though I like the pieces individually, it's a lot of wood all together.

It makes me wonder if you wouldn't suddenly like some of these items a lot more if they were in the context of more variety. So you might start with the easiest thing to change and progress towards the most difficult/most expensive to change and stop at each stage to assess if your desire to paint everything has abated somewhat. I'd also suggest considering materials other than stained or painted wood for more contrast -- metal, glass, fabric, etc.

So start out by getting yourself some cute new stools (maybe red?) and maybe add some more/brighter art and interest on the walls. Then get yourself a new table and chairs and plop it next to your kitchen and built-in. If you're still not happy, then paint the built-in. If you're still not happy, then go through the whole thing of painting all the kitchen cabinets.