I think there is semantic scope inherent in the saying "don't invest more than you can afford to lose" than in its most literal sense. This is important because I fully agree that bitcoin is amongst the best asymmetric bets. When you are young, you have no children and no serious obligations to fulfill other than your basic needs, then there is some scope for additional risk taking and I think there can be scenarios where you feel very convinced that
The fact is that you did not invest in bitcoin those early days is because you don't believe in bitcoin and that was why ypu could not take the risk because you said that you kept the money which means that you still have an amount that you can afford to lose but you don't trust bitcoin price going upward trend.

A lot of us have made mistakes in the past and neglected to invest in bitcoin due to ignorance and lack of understanding the potential of bitcoin and it is bringing regrets now but as long as bitcoin price is cheap using DCA will help us accumulate gradually, slow and steady to reach a good bitcoin size in order to console ourselves from missing out the early days of bitcoin.