Currently I have less than 5% of my personal wealth in bitcoin, and since Im not that wealthy then that means I do not have a lot of BTC, but I plan to put at least 20% of my wealth in five years
the point is, it doesn't matter how much you invest ($1 or $1Mil) what matters is that you only invest what you can afford to lose. that is the first rule of any kind of investment.
you make an assessment of the risks and rewards and if the ratio is good enough you then think about how much you are willing to put in.