I perform well in areas I have interests in. Thus, by coincidence, I can appear capable in those areas.
I'm also shockingly stupid in other areas.
I've noticed a few things about how I learn: it has to be practical. Nothing theoretical will stick, unless put into practice. Thus, school was hell.
I am also a devilish combination of a very slow learner who thinks differently about things. When a teacher taught things to the class, everyone got it immediately and I always somehow managed to come up with my own, weird, wrong interpretation of things.
Once I have finally learned something, I am very accurate and precise, which is fairly useful in the fields I've worked in. I also have a flexible mind, which is great. I can usually reason outside of the confines most people think within. Which, see school, can be a blessing or a curse.
I've met truly intelligent people. Like, real freaks of nature types. PhDs in aerospace engineering, that sort of thing. Their universal intelligence is something else. It has shown and demonstrated to me beyond a shadow of a doubt that there are levels of comprehension, both in the uptake and subsequent processing of almost any information, that I will never reach.
But don't for a minute think that these were happy people.
You sound like the textbook definition of someone with autism or on the spectrum.
I am diagnosed and the following applies to me from your comment
Excel in special interest topics.
Kinda srupid in not interest topics
Prefers practical over theoretical knowledge and application
Disliked school due to (above)
Think very complicated to understand a topic
Haha, well, I've had many people tell me that I might be and I've had my own suspicions for a while.
I am terrible in social situations (actually really good at them, on the surface. Good at pretending, but I hate it), I hate crowds, noise, flashing lights etc.
But honestly, at this point I'm not sure what difference a diagnosis would make.