And this here is the root of your error. As I said in my other reply to you, you obviously don't know the nature of your first person perspective, that is, your personhood. The same personhood which is, even objectively, and by scientific standards very own to (at least) all mammals and birds (though I would, personally, go much much further). As you can deduce, that makes our nature rather inhuman (and as a side note, creatures you call animals, as if human was not one of them, can exhibit decisive measure of self-control).

Whether you like it or not, no matter the social progress or lack of thereof, you will be always "tied down by natural causes." Though I must add, that in my case I perceive them not as a chain but as an unbreakable bond that connects me to everything and has nothing to do with my freedom. To each their own, I guess.

All in all, you are suffering exactly because you rebel against it and want to separate yourself from your own nature. However, you will never be able to leave this universe. Like where exactly would you like to go anyway? Frankly, if the vast knowledge we got in the last few hundred years does not empower you but makes you existentially angsty, there's no helping you (before you jump to conclusions — I mean that helping part metaphorically as a manner of speech).

And last but not least, where did you get that image of "ancient naturalistic sage" detached from this world? That's one of the textbook mass fictions you decry so loudly. I guess, the main difference between modern and ancient sages is merely that most of those modern wannabes still didn't go past self-centered whining and self-pity ¯\_(ツ)_/¯