The Concept
The ‘Learn in Two Weeks‘ concept was originally introduced by the Math Sorcerer on YouTube. He is acutally talking about math in the video but it could be generalised to other fields.
The idea is more recently promoted by @yacineMTB on X.
‘If you have a project, combat Hofstadter's Law by setting a ridiculously ambitious deadline. Even if it takes three times longer than the deadline, you're ahead of everyone else.‘ - Elon Musk