Most things aren't very complex, if you divide them into small enough chunks. My niches are IT/audio/music. Many things in those can be initially offputting to newbies, but like 99% of what I know is not very hard in and of itself, it's just hard because you lack the context of other things that are related but separate from that thing of itself, and those things are not that hard either. Most of the time all attempts to explain it to you have been just bad and convoluted, trying to explain several things at once.
When learned some music theory, I was almost angry at how hard my previous teachers had made some simple things made them out to be Like you could had explained that in like two or three sentences and elaborated on that, I would had understood immediately.
And many things even in seemingly unrelated categories share a lot of concepts, or at least similarities. Once you are knowledgeable about few subjects, it is really easy to build upon that, and learn other things quick, if they have any common ground with it.
Especially when you learn to make useful oversimplifications/heuristic thinking that are good tool to get a grasp before you dive into properly understanding the nitty gritty. This is dangerous if you don't keep it in check, my manager seems to be only able to think this way, and doesn't properly understand anything. But it can act as a filtering layer when presented with too much information, or incomplete, low quality information. I have done technical support and most problems are fixed like this, hence the classic " have you tried turning it off and on" default scenario. If it doesn't work I actually engage my brain with it.
Thinking you are very smart, even if you are, is usually bad feature to build your personality around. Ofc it is good metacognitive skill to understand your strong features, and if intelligence seems to be one, more power to you. But smartness is just one thing, and you can't objectively evaluate it. Plenty of "smart" but not wise people fucking shit up as it is, and you will likely have better luck with people if you don't overindulge in this type of thinking.
I certainly have that, but have always also though thinking you are a fucking genious is counterproductive for ones learning and possibly social relationships, so I have tried to limit its hold of me, although not always successfully.
That being said, one last advice, most people are not very smart, and even if they are, they might be doing things out of external reasons, not internal. If you have at least modicum of intellect and lots of passion, it's not that hard to be better than the most with just the power of genuine interest and longetivity.
Getting hired based on that skill is another thing, but if you truly care about getting good at something, you will soon realize many people aren't even trying, at least on the standard for "trying" you have for yourself, and you will slowly but surely get better than them at that skill even if they are initially better. Not that it even matters as much to you as it does to them because you care about the thing itself more than their opinion.
While some things might need some natural ablities or benefit from them, most things can be learned with enough reps and continuous evaluation of your learning skills while at it.