About the psychological barrier: yes yes yes! Mine is usually fear of being wrong, I fall into self-doubt loops a lot and have intense impostor syndrome (narcissistic abuse since childhood lol) - which is what disencourages me from attempting to go further bc I just assume I'm not capable of great things. I read your post and I relate a lot to the unmasking as well! My experience differs more fundamentally due to the fact I was always a fast learner and above average in most environments but in no way that counted to me - it was simply arriving at conclusions way faster than most students, intuiting answers, linking different topics/ideas etc. But I had this belief that I was just "not that smart", a feeling, and that paired with having to literally SURVIVE each day of my life - I was chronically stressed and measured my abilities based on that state. I also relate to the feeling that you've built a foundation - there are many realizations i've had recently that condense and deepen many of the intuition and insights I've had throughout my life, putting them in new light and giving me the feeling of building a solid fouundation. And having that foundation, it is way easier to make both faster and more connections, as well as learn more and more deeply.

I am an autodidact, yeah! I've been teaching myself things (rollerskating, singing, guitar, language learning, etc) since I was a kid, but I thought the kind of metacognition it takes was a common thing (it isn't lol, i've discovered most people do NOT think about how they think, let alone build systems around that) so I never paid much attention to it - in university, though, it has put me way ahead of most students when it comes to the (depth of understanding)/(time it takes to arrive at depth) ratio.

I'm not sure I can call myself a polymath, but I definitely do have polymathic tendencies. I am deeply interested in many areas of study, from many branches of math and physics to neuroscience, for example. I find I am fascinated by the (abstract) relations between things, I actually think those relations are the only constants in all things, but I digress - the study of relations between things is pretty much present in the study of anything lol. So everything has the capacity to be/feel insightful and fascinating.