If two things are equivalent, A<->B, does that mean they represent the same math object?
Barry Mazur has a really neat paper on this question, and at least parts of it are quite accessible. He ends up advocating (maybe just "showing the benefits of" is a better term) of an approach grounded in category theory.
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://people.math.osu.edu/cogdell.1/6112-Mazur-www.pdf&ved=2ahUKEwjZhPfV0qCJAxW9vokEHYuQCMwQFnoECB4QAQ&sqi=2&usg=AOvVaw0j1f7DfoQP7OKuvRZ37rIU
Mathematics thrives on going to extremes whenever it can. Since the “compromise” we sketched above has “mathematical objects determined by the network of relationships they enjoy with all the other objects of their species,” perhaps we can go to extremes within this compromise, by taking the following further step. Subjugate the role of the mathematical object to the role of its network of relationships—or, a
further extreme—simply replace the mathematical object by this network. This may seem like an impossible balancing act. But one of the elegant–and
surprising—accomplishments of category theory is that it performs this act, and does it with ease.
In a very loose sense, there is a neat parallel here to Roveli's Relational Quantum Mechanics or some forms of process metaphysics. I am less hot on those than I used to be, coming around to views that still include a role for the nature/essence of objects (e.g. Aristotle, or some interpretations of Hegel—things might be defined by their relations, but they are not
just collections of atomic relations, rather relations are defined by what a thing is as a whole), or Deely's Scholastic-informed semiotic view of things existing in a "web of relations," which still holds on to "realist" intuitions re essence—a "balancing act." (Well, that's all vague I know, but the paper IS interesting!)
And there is also a neat parallel to St. Maximus the Confessor's philosophy and the Patristic philosophers' conception of number, which I will perhaps return to elucidate if I have more time. But basic idea is that things are not intelligible in themselves (although they do have intelligible natures, logoi). For instance, the idea "tree" is only fully intelligible in terms of other ideas such as the sun and water that are necessary for the tree, the soil it grows in, etc. You cannot explain
what it is in isolation. Numbers and figures (following the old division between magnitude[discrete] and multitude[continuous]) are included here, in that they only exist where instantiated, in minds or things, and are not wholly intelligible on their own.
This makes even number
dynamic in an important sense. To be fully intelligible, things must exist in the absolute unity of the Logos (Christ as Divine Word, but due to divine simplicity we might say God as a whole as well—on this view the entire cosmos is incarnational).
Anyhow, this sort of relates back to the OP. The idea is that, yes, there is a sense in which everything must be one (i.e. unity in the Doctrine of Transcedentals), but there is obviously also differentiation and intelligibility in the many (the old problem of the "One and the Many").
Another interesting thing is how this relates to knowledge. In Metaphysics, IX 10, Aristotle distinguishes between two kinds of knowledge/truth:
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Asytheta: truth as the conformity of thought and speech to reality (whose opposite is falsity); and
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Adiareta, truth as the grasping of a whole, apprehension (whose opposite is simply ignorance).
Obviously, we follow relations discursively, through asytheta. But then it is by coming to grasp the
whole (via adiareta), the principles by which these relations obtain, that we gain a more full understanding (St. Maximus gets at this in
Ad Thalassium 60). Likewise, in the
Arithmetic Diophantus*, although generally dealing with problems whose principles he cannot discover, makes the case that solutions are
virtually present in the principles that will allow for solutions (the "many" contained in the "one," e.g. many shapes, with their own distinct quiddity/whatness, flowing from Euclid's postulates).
*Interesting bit of math trivia, Diophantus, living in the third century, seems aware of Lagrange's four-square theorem, and if he had an actual proof of it then it was effectively lost for 1,500 years (we only have some of his books).