It's in these new found fears and anxieties. Genetic predispositions to painful or deadly diseases can make some feel trapped by some biological destiny. Psychology or neuroscience can also make some feel trapped by brain chemistry or childhood experiences (even compound the anxiety of biological destiny). Climate change can be the source of much existential dread. The interesting question is how does the Epicurean respond to these new problems?
First and foremost I'd say that Epicurus would say to take heart in looking at the truth without sugar-coating it, and that we can be grateful for the good things that we do have. Then he'd say that the way things are are the result of specific combinations of atoms and void, which are not required to be the way they are by any force of divinity or necessity or fate, and which -- if we try hard enough and long enough -- can often be changed. No doubt lots of things can't be changed, at least within our own lifetimes, but the pleasure of thinking that you have faced down the truth and fought it with everything you have is not something that we should think of as belonging to the Stoics. After all, they think that every external thing that happens to them is a grim matter of divine will / necessity / fate anyway.