In the verse of chapter 67, verses 3-4. What would be the TRUE interpretation of the "7 heavens being stacked one above the other". Furthermore, in order to actually understand the stacking of the heavens, one must understand what "heaven" really mean physically. Also when Allah (SWT) in this verse talks about "where you see no flaw in the creation of the Most Merciful" here the word "flaw", I have read to be synonymous to inconsistency/un-uniformity/ asymmetry, can we interpret this verse to be that one may never find "inconsistency" in the law of nature with another, where the mathematics and physics don't break down mid-way as it goes on to perform a function. Can it also be interpreted as the mathematical symmetry that we seem to observe in the universe? All in all, what is the true and complete interpretation of this verse in question?
One understanding of this, but not necessarily the only one, is that they're layered like the layers of an onion.
can we interpret this verse to be that one may never find "inconsistency" in the law of nature with another
Yes, that seems to be the agreed-upon interpretation, although it wouldn't be mathematical symmetry, as symmetry means inversed mirroring. It would be mathematical consistency.
All in all, what is the true and complete interpretation of this verse in question?
We don't have the capacity nor the tools to comprehend the "true and complete interpretation" of verses of the Quran as Allah says in Surah 3:7. The benefits of Quran verses is not zero-sum. You get more insight as Allah bestows more knowledge on you.