I thankfully was able to obtain a copy of R Moshe Shamah’s “Recalling the Covenant,” which includes his commentary on the biblical censuses as well as an appendix on biblical number symbolism and the usage of numbers in the Hebrew Bible, apparently based on the theories of the polymath R S D Sassoon (whose only book I have is his work on theoretical physics).
And all I can say is that I’m more perplexed than ever regarding the tallies of individuals in the Torah. 
Are they intended literally, and just happen to be both improbably large and skewed while exhibiting many signs of fabrication?
Are they intended non-literally, and the historical truth was considered unimportant to record in comparison with encoding symbolic ideas that only a select few of careful readers would be able to (even know to) decode?
What does the answer say about the meaning, purpose, and accessibility of the Torah? What does it say about the meaning of Torah as a divine message? What does it say about the meaning of our collective memory of our history?
What does the Creator mean with any of this?
I don’t know.
The search for truth is messy.
Sometimes you just gotta live with the perplexity and trust the God of truth to some day enlighten you.