But ratios only express rational numbers, if we had to express location in a 3D continuum it's almost guaranteed that it would be represented by an irrational number.
Fair point and I don't necessarily disagree. I don't like the consequences of superdeterminism, just playing devil's advocate. If we exchange simple ratios for fractals we could have compute based infinite precision. Precision would just be a matter of scale of the measurement.
So if there is superdeterminism, meaning positions are absolutely determined, either there is minimum scale in the universe (discrete universe) or somehow the universe computes with infinities.
Both are absurd concepts! When probing the ultimate depths of reality like this there are no good answers.