You are erroneously conflating investing with gambling. Astute investing in index funds is essentially risk-free if your retirement is far enough away. As you get closer to retirement, you should start moving from funds to bonds (or cash if you want to be extra safe), so you are protected in the case of a crash.

I am not OK with losing the money I have invested, but it is so unlikely that I do not need to worry about it.

A situation where the global stock market crashes, and never recovers, is basically an apocalypse. That is not worth planning for.