Well, put bluntly, the reason is that you probably are not using the Nikon properly. So, your photos are not coming out that great or as you hoped. Don't take this personally, I also have my limitations using cameras properly. But I understand I'm an amateur when it comes to this and that I'm part of the problem. I try to learn to do better. I try, and sometimes it works out nicely and I get a really nice shot. Landscape photography is tough to get right. You really need to understand your camera and lenses to make that work.

The point of such a camera is not the in camera processing, which most pro users would not use on principle. Instead it's gaining a lot of control over setting up the shot properly with a lot of control over all the parameters that matter to achieve a look that matches what you want, intentionally. And then you finish the job in post processing. There's reason these things have so many buttons and dials: you need to use them to get the most out of the camera. And the point of owning such a camera is having that level of control. The flip side is that that makes you responsible for the intelligence. That kind of is the whole point. If that's not what you wanted, you bought the wrong camera.

The iphone has a very limited set of controls. You actually have very little control over it. Nice if that's what you want and the AI is awesome. But it's also a bit limiting if you want more. Of course it's very nice when that's the camera you have and you want to take a shot quickly by just pointing and clicking. Nothing wrong with that. I have a Pixel 6 and a Fuji X-T30. I use them both but not the same way.