I agree with large chunks of what you say; but caution:

There exists no supernatural forces in the world and there is no objective morality imposed from above.

Those who believe in supernatural forces "above" us, often think they believe in objective morality. This does not imply either that belief in a God implies belief in objective morality, or that belief in objective morality implies belief in a God.

(It's ironic, and a major source of confusion, that Christian "morality", which is often used as the prototype for "morality", does not address the problem of "where does oughtness come from?", any more than positing a God addresses the problem of where life comes from. It's the same cheap trick in both cases.)