Pareto distributions are everywhere, and most learning ends up being one. Recently encountered this while getting into weight training for hypertrophy. The core is good form, diet, and progressive overload. Other than that, learning the basis of a specific exercise is something you can pick up as you expand.
It's so similar to most of the things I've specifically sought to learn as an adult. You get so much bang for your buck, time-wise, when learning something new. The best part is when you don't even need to dig deep past that foundational 80% and you can become pretty knowledgeable about something in a very reasonable amount of time.