Epicurus' fundamental pivotal importance to me is, at its heart, the firm knowledge that the universe is material, governed by natural laws, not created by supernatural beings, and gods (which are NOT supernatural to him) have no interest in us. I don't need to believe in intermundia, cosmoi, gods, etc. to be an Epicurean living in the 21st century of the common era.
I enjoyed your overall post in which you ended with the above thought. I guess I'm not an Epicurean but rather a student of Epicurean thought and an adopter of many of his methodologies for discovering knowledge.