Try posting a couple photos of the ENTIRE kitchen. Both sides.

No magic. You’ve got what you’ve got.

Rolling cart with nice shelves underneath would be great in that space. Boos makes really nice ones. Ikea makes perfectly serviceable ones.

A new run of cabinets under the window would be 24" deep, which means it would create a corner where your dishwasher is on one side (you'd lose the dishwasher space) and you would lose the cabinet next to the range on the other, jamming the range in the corner. So, if you wanted to create the U, you're likely looking a fairly major reno.

How wide is the space? If those tiles are 12x12, you've only got 4ft? I agree that a rolling cart (that you can move out of the way to access the current side cabinets) is your only option.