The most heartbreaking summary

The long-term bull market in US stocks,

earns "patient money",

loses "human nature money".

The index always goes up,

but human nature always chases rallies and sells on dips.

That's why there are still casualties all over the place even in a bull market.

The path you're on now:

Dollar-cost averaging into ETFs, low leverage, no option gambling, holding on

—is exactly the only surefire route to profit in a long bull market.