Not sure if you are trolling but if its a serious post then stick to your iPhone X.
Work on your skills rather than gear because gear won't help you with anything.
Give great photographer and iPhone X and he will do the most amazing things with it.
Give a novice D850 and the best glass and he will produce pics that won't beat the guy above. Its that simple.
I think the OP is trolling, so I hate to bump this thread.
I agree with your sentiments as they apply to the OP--good photography requires skill and experience. It is a mistake to think that better gear will necessarily result in better pics or that better gear can compensate for a lack of skill and experience.
However, your response is somewhat hyperbolic. Better gear *will* result in better IQ for a given subject, depending on how you define "better" gear. While the iPhone X has a decent camera for a phone, the IQ of the files is nowhere near that of a D850. This spring I went on a cruise with both a D850 (and Sigma 40mm f/1.4) and an iPhone Xs. I used an app for the iPhone that lets me shoot in RAW. The RAW files from the iPhone Xs were horrible (especially in anything other than really good light). I ended up impressed with just how good a job the iPhone Xs software does in creating its JPEG images.
The pro with an iPhone vs a novice with a D850 is an interesting rhetorical argument. It has its merits in pointing out that becoming a good photographer and creating compelling images is a skill that requires practice, dedication, and experience. But if the IQ of images produced with an iPhone were *really* as good as images produced with a better camera, then all photographers (once they reached a certain level of competence) would only be using iPhones. Which is a silly idea on any level.
Give a novice an iPhone X and a D850 with 200-500mm lens and ask them to take moon pics. The iPhone pics will be worse. Give a novice an iPhone X and a D850 with a 70-200mm f/2.8 lens and have them take pics of a kiddo jumping into a swimming pool (assuming they are competent enough to move the dial on the top of the D850 to continuous release rather than single release and maybe change AF to continuous). The iPhone will be worse, even with the D850 in program mode. Give a novice an iPhone X and a D850 with a macro lens and ask them to take a picture of a ladybug really close up. The iPhone pic will be worse (though to be fair, depending on how macro you need to go, the iPhone can take pics reasonably close up).
For all of these examples, a professional with an iPhone X would struggle because the iPhone isn't a good tool for any of those applications (as well as others). It is not good for telephoto (especially extreme telephoto), it's not good in low-light (though it does an impressive job in software of making low-light JPEGs look decent), it's not good for action photography. A professional would have a better understanding of the limits of the iPhone and be able to work within those limits, but certain pics are not possible with an iPhone regardless of your experience/talent.
I completely agree that photographer skill is much more important than gear in a general sense. "Good" photos are most often a reflection of good composition, appropriate light, and the right combination of aperture and shutter speed for a given subject. Buying better gear doesn't magically change any of those variables--only skill and experience does.
It is silly to assume that better gear will automatically translate into better pics. But it is also silly to assume that gear doesn't matter at all. It can and does. But before buying better gear, it's important to ask yourself how *exactly* is your current gear limiting you and how *exactly* will a proposed purchase "fix" these identified problems. A novice generally can't answer either set of questions meaningfully in the way I intend them. "Making my pictures better" is not a meaningful answer in this context. What is the *specific" problem that this purchase will actually fix? Not marketing hype, but actual ability to fix.
Is it a "you" problem (I'm not sure why my images seem to suck, but they don't get enough upvotes) vs an actual gear problem (I like shooting in low light and my kit lens with a maximum aperture of f/4 always results in either underexposed pics or pics that have such a slow shutter speed and/or require such a high ISO that they are blurry and grainy, does it make sense to buy a faster prime lens (f/2, f/1.8, f/1.4) to fix these exposure problems?)? In the former case, throwing money at the problem is unlikely to fix it. In the latter case it might.