The introduction of Warren's Cambridge Companion On Epicureanism says its chapters entitled "Epicurean atomism", "Cosmology and meteorology", "Psychology", and "Action and responsibility" are the ones which discuss "the major subject areas" of "physics and metaphysics".
I suppose "metaphysics" really does need an obligate qualifier, such as "esoteric metaphysics", "Platonic metaphysics", … in the same way as one wouldn't write in a vacation postcard "Dear friends, we landed safely. There is weather." Instead, weather is one of those words, which always need further qualification, too.