You have a very poor mindset of what it takes to successfully build and sustain a Bitcoin investment. First, you should adjust this mindset of investing what you can afford to lose because such mindset will only make you afraid of even investing in Bitcoin because you cannot intentionally put your money where you will lose it. There was a reason it was recommended to invest only discretionary income because that is the money you can keep
Investing with money you can afford to lose does not mean that you will lose the money. It is never said that you will definitely lose the money you invest or that the probability of losing is high. Investing with money you can afford to lose means that if you unexpectedly or accidentally lose money in some way or if you lose access to your funds, it will not have a serious negative impact on your real life. Although the probability of losing this money is very small, we should still plan and take precautions for even the smallest possibilities.
If you just think that you can lose your money due to price volatility or that Bitcoin can disappear from the market one day. Then you are wrong. Although I will not guarantee this, the probability of this happening is less than 1%. However, there is a possibility of losing access or your funds can be hacked or you can lose it somehow. There is a possibility that this could happen, we cannot rule out this possibility. This is also one reason why the idea of investing unnecessary money is to avoid needing that money in the long run. Considering all these things, it is said that you should invest money that you can afford to lose. But you are not losing that money intentionally.