2. Invest what you are able to lose;
I have a question!
Who has ever lost in bitcoin?
Are you serious? Anyone who bought in at above the current price is at a loss. "You don't lose if you don't sell" is nonsense and nothing but a coping mechanism.
But with bitcoin having proven that it can resuscitate after crash, the advice should be rephrased as Invest what you will not be needing in the next few years. It will not be advisable to use the money meant for your childrens school fees for bitcoin. Just have an investment budget from your income that will not negative alter your living state.
What you're proposing is not much different from "don't invest more than you can afford to lose", the only difference is that you seem to guarantee that BTC will keep breaking the new ATH every "few" years. Nobody can predict what will happen in the next few years, and there are good arguments out there for the next cycle to not reach the previous ATH.
I'm sure you wouldn't be giving such guarantees outside of an anonymous forum if you could face legal consequences for giving bad investment advice.