The cabinets, floor, paint & backsplash all appear to be in a beige tone. The countertop goes with all of them.

If you don't want to re-do anything major, then I'd recommend using items of decor and kitchen necessity to bring in upgrades. Things like brass or metal toned decor items to add some splash...........or a color you love like turquoise, blue, or bright green.

Without re-doing something major, changing the overall appearance will not do much. You could choose a color you like, maybe a sage green or beige-ish yellow to paint inside the inset in the ceiling to draw the eyes up to the color, then add some items in that color. Even cookbooks that have brightly covered spines on the kitchen counter, with cool book ends can help introduce some splahses of color. Find a really nice small lamp you like in a metal tone and put it on the counter as an accent. I have a lamp on my counter AND on a bookcase to add some delicate lighting.

One thing that may spruce up minimally is a "tin" backsplash. Can you remove the little backsplash without damage? The tin tile squares sort of mimic the floor and complement the counter and floor but installed not on the diagonal. This is a bit too ornate...

The good thing is - your kitchen has neutral colors and Stainless Steel appliances so it's easy to update. I think black or darker granite countertop would add some contrast to pale shades in your cabinets and tiles.

I like quartz counter tops. However, in a U shaped kitchen like your if you go with granite or quartz you will likely have to deal with a couple of seams. If that is an issue for you look at some of the new Corian and Hi-Max colors. Once you choose your counter top you can pick out back splash tile. You may also want to improve functionality bi upgrading your sink and faucet. I love the New Cast Iron sinks by Kohler as well as the faucets by Kohler, Moen and Delta /Brizo. Last but not least consider updating the lighting. A good LED package will improve looks and functionality.