Yes, yes! I tell my students in Ethics courses that "your ethics reflect how you think the world is." You are so correct that Stoic ethics and practices are a direct result of how they thought about the world, their metaphysics. Your warning about the darkly pessimistic cliff is so apt.

I am all for learning about multiple philosophies and traditions, and incorporating ideas from them into one's own life and practices, but always with an awareness that every philosophy and tradition has both positives and negatives.And yes, careful not cross that event horizon.