In this way, wholeheartedly embody the endlessness and roam where there is no sign, fully realize whatever is received from Heaven, but without thinking anything has been gained thereby. It is just being empty, nothing more.
"Without thinking anything has been gained thereby" is a phrase with immense implications. It is reminiscent of those words purportedly spoken by Buddha which go something like this: "When I attained absolute, unsurpassed enlightenment I gained absolutely nothing; this is why it is absolute, unsurpassed enlightenment." Zhuangzi's "add nothing to the process of life" is, in my opinion, more radical still, if it is indeed the abandonment of hypotheticals and redemptive avenues of escape that is implied by "gaining nothing". Buddha "gained" enlightenment, became something other than the mundane, was "saved" from the curse of existence, was freed from the fearful wheel of rebirth, got to understand how things really are, got to somehow pre-exist life and transcend death while denying he had anything to say on the subject — he got to have his cake and eat it too. Buddha got religion, or at least became the seed of one. None of this on offer in Zhuangzi's way; what you experience is what you get. This is not about getting saved, but about "fully realizing" one's humanity with all its existential unfixedness.
"Just be empty." If there is no identity fixed and sure, no soul to start with, how could anything be "gained"? Add nothing to nothing and what do you get?
If it is religion we want, and by default we do, then Zhuangzi's philosophy can certainly become just that. It did. Daoism is a religion. It provides answers. It offers salvation. It is populated by entities, fixed and real. It reassures us about death, that it will be overcome. It provides all those things that religion does, all those things that deny our actual existential circumstance, because we find them too fearful to squarely face and affirm. Yet, it is precisely this that Zhuangzi sought to leave behind; it is precisely those things that religion denies that Zhuangzi saw as the means to an authentic transcendence that "fully realizes" the very tenuousness of this life experience.
There is a sense in which this path of not-knowing is a constant struggle against the impulse to religion within us. If this is so, then we are likely to discover in our perpetual self-critique that this way has become religion for us. Of course it has. This is what we do. Yet realizing this is precisely the means by which we "chariot upon" it, not in denying it, but in embracing it, and in so doing, experience "our homeland of not-even anything, the vast wilds of open nowhere".
You can check out Scott's writings on Zhuangzi here.