I worked full time in data science during my last 2 years of undergrad and I'm pretty sure the process to pull this off is reproducible.
If you hammer prerequisite concepts/skills into your long-term memory, get it really solid and easy to retrieve, then you can lessen the load on your working memory, keep it below capacity, avoid getting "broken," and keep up with the game.
When it looks like someone progressed so fast they “must” have taken a shortcut, what really happened is they speed-ran the foundations.
Making progress is really enjoyable. People typically find math (and other challenging activities) enjoyable by default and it’s really just the feeling of slow/stagnated progress that makes it unenjoyable, especially when coupled with overwhelm.
Nobody is born cracked.
Why jumping the gun on complexity leads to compounding struggle.
People acquiring impressive skills so quickly that it's mind-bending.
“Schools do not seem to have a great tolerance for students who are out of phase with other students in their learning process.” -Benjamin Bloom, 1985
Lots of people consume. Fewer people actively do. Even fewer people attempt challenging things. And even fewer people than that build up the foundational skills needed to succeed in doing those challenging things.
When someone fails to make decent progress towards their learning or fitness goals and cites lack of time as the issue, they're often wrong.