Epicurus had great instincts. He was pretty damn close to things modern science has discovered. As you mentioned, he was an atomist. He also said you can generally trust your senses, but they can be wrong and deceive you at times. His ethics of moderation and valuing relationships is spot on when it comes to life satisfaction.

It’s interesting you mentioned naturalism in the evolutionary sense. Have you read Darwin’s book? Darwin’s ideas aren’t entirely original, he himself pretty much says that, but his data collection and observations were something that hadn’t been done on that level yet.