1. Sorry, but I don't understand your use of the phrase "solo person." Do you mean working from home, working as an independent contactor, working without a team (for whatever reason) or something else?
And it depends on what you are using AI for. In most cases, I won't have an answer for that. But in some cases, I would. In short, I need more information to provide advice.
2. Similar to the first answer, what does "validated learning" mean to you. However, beyond that, I can recommend a book that was an amazing help to me in terms of quickly learning a subject.
The book is titled, "The Science of Rapid Skill Acquisition." It's an exceptional book. Also, Gladwell's "Outliers" is helpful in the sense of realizing why some seem to just be better than others when in fact they are not. It just seems that way. In my view, maximum productivity is about focus and effort. Which reminds me, the classic book titled "Flow," by Mihaly Csikszentmihalyi, was also an amazing help to me.