tl;dr: software developer
Software developer. Unable to thrive at school or university, I had phases ever since I had a PC where I self-improved with more or less intensity. A few years where I had neither energy nor motivation, but discipline to do a little bit most days. Just a solid hobby-level.
Then out of nowhere It became an obsession for 5 years, like it usually does for a substance or gaming addiction. Just wake up, immediately study, trying to get everything perfect, to understand all the competing approaches and their reasons to every problem, only sleep when I can't keep my eyes open.
Finding mentors online, big names in their niche. Most people think that these people are annoyed from hundreds of "fans" who want to learn, but actually, that rarely happens, and when they see how much effort you put in, they are happy to help. One day, the phase ended as quickly as it had started. But I still had the knowledge.
That was 20 years ago. Much of the stuff from back then is still relevant, but there are the massive changes to web clients, and there are "clouds". In relation to relevant frameworks and standards, I'm far less skilled now, but I have two decades of reference projects which make me LOOK better.
A problem is that working away from home really doesn't work for me, thus having to refuse > 95 % of offers (they just come, I don't apply). But since 2020, that is no longer an issue.