Hi and welcome to YT. Buster would pee in the hallway where I kept him as a puppy for a long time until I started cleaning the area with an enzymatic cleaner as the smell would entice him back to that spot. He is much better now and usually pees on the pad though I wish I could convince him that all four paws should be on the pad not just the front two.
Perhaps you are giving him too much room in the kitchen? I am hoping others will respond with good solutions.