The concept about your topic is one that I actually like, especially how you so detailed your first point on what you could afford and it makes sense. What I don’t very much agree with is your take on what you can afford to lose.
2. Investing what you can afford to lose: this means that you're using your money to buy something that you can lose at any time. If that's the case, it means it will be unwise for someone who's earning 200k per month to keep investing 40k for multiple years.
Don’t be so literal to its meaning else, you would miss the point in that phrase. It doesn’t necessary mean you’re losing that money. It simply implies you’re ready to take in whatever the outcome might be. A clear understanding of a risky investment and being ready to go with it either ways.
That’s what Bitcoin is and having to define this guides your investment choices.