Ive always thought of it like this. Psychedelic Trance is the mother genre, then we have goatrance as one sub and also psytrance as another. Yes that becomes a bit confusing since both share the same name; but they are indeed two different things.
for example goa is like astral while psy is like infected. Of course thats just how i have looked at it personally for all these years. I dont remember anyone even calling it "psytrance" until a bit later, early 2000s i think. But maybe we did call some stuff "psy" even earlier than that... Hard to remember.
Anyway i think "psytrance" as a genre is mother to sub-genres like dark, forest, tech, etc. While Goa and "Psy" has always been slightly distinct flavors under the matriarch; "Psychedelic Trance".
makes sense to me at least