It sounds like you're arguing that since all these traits are used to determine between a single binary classification (or spectrum) in different ways that there's no multi-dimensionality but perhaps you're misunderstanding.

If biological sex is something that can be accurately represented in a certain multidimensional space then every axis will necessarily have the same type of value (a range from female to male) but a different orientation (or trait being evaluated). This is the same as how you place a mathematical point in space by using 3 axes with the same type of value (-inf to +inf) but different orientations. You need all 3 axes to place the point and can't collapse its location down to a single axis. Similarly we should understand biological sex as something that can be measured by specific traits but never collapsed down to a single value and thus is intrinsically and inescapably multidimensional.

Female to male is one dimension of measurement, yes, but that's only meaningful for individual traits. An individual has many traits and so must be described in multidimensional terms even for a single metric.