I'm not so bold as to propose I'm a master yet, but I've definitely hit a patch of "these problems are plaguing the industry and lots of smarter people have not managed to fully solve them yet."
What's been fascinating is I now have sufficient perspective to have thoughts and hypothesis of how to approach solving them, but the experience to have a sense of where I'll likely hit walls.
In the case of business it gets interesting because in many cases, if these problems have been solved, there's vested interests in making sure nobody else finds out how you did it, so these may actually be solved by some companies already and I'll never know.
Nor might we know when a teacher or mentor is communicating something textbook vs. some non-textbook insight or new idea.
Doesn't mean I don't hold a strong view on some subjects, experience has also solidified things that time has shown as essential.
This doesn't seem like a bad thing.
Maybe people just realize as they grow older how complex things really are, and eventually learn not to fall for the dunning Kruger effect on everything
Both these accounts fit with lower levels of testosterone with age...
If you actually have low testosterone, many doctors will prescribe supplements. It may take some work to find one who doesn't consider age-related decline to be "normal", and so not warranting treatment. And if you can't, then you'll need to shop online.
They are a content farm owned by Internet Brands and their only focus is creating content as vehicles for pharmaceutical and consumer packaged goods advertisements.
But there's a problem, if your testosterone level is too low. In my experience, that increases the risk of tendonitis. Also, it didn't seem that exercise did much good. At least, not for strength training.
But with testosterone supplementation, exercising builds muscle and reduces fat. And no tendonitis. Also better blood sugar management, and less acne. Maybe even darker hair. But clearly not more hair on my head.
On the other hand, this effect doesn't seem to be limited solely to men, so while I may have mellowed with age, I don't think that's the only thing going on here.
In my mid-30s, I'm much less confident about just about everything. I still have some medium to strong opinions, but I've been wrong enough times about things I was sure about that it's just hard to hold such strong views on things having only read it in a book or two.
There are a couple of differences between your experience and mine though, I think. The first is that I'm about to finish my PhD and have a great deal more expertise than I did in my early 20s. So as my expertise has grown, my certainty in many things, especially those outside my field has diminished. This is largely because I realize just how much more depth most fields of knowledge have and just how much is required to really hold an informed opinion.
I also deal with a fair number of young people, college students in my department and in other contexts. I recognize some of the same certainty and optimism I used to have at their age, and I hear some of the same opinions I used to hold on such things as vegetarianism, government systems, and economic policy. I remember having those beliefs, and talking to these young adults, it's striking just how little evidence their certainty rests on. It's worse inside my field, where students come in with their "great idea" having done no research and spent all of about 5 minutes really thinking through the ramifications of their idea, but that same certainty and optimism is there.
I often wish I was as idealistic and energetic as I was 15 years ago. But I wouldn't trade it for the naive surface-level thinking that went along with it. I like seeing the depth in the world too much, even when it shows just how shallow my thinking is in most areas, and even if it means that in most areas of life I'm forced to constantly face my uncertainty and lack of expertise.
Anyway, I hope that was at least a little bit helpful.