How can I create latex-like subequations?

Questions
1

I want to create latex like subequations. Using the following code

#let subequation(..it) = (
  figure(
    {
      context {
        let n = counter(math.equation).at(here()).first()

        let c = counter("subequation")
        c.update((
          counter(heading).get().first(),
          n + 1,
          0,
        ))

        set math.equation(numbering: n => {
          numbering("(1.1a)", ..c.get())
        })
        for i in it.pos() {
          c.step(level: 3)
          block[ #i ]
        }
        counter(math.equation).update(n + 1)
      }
    },
    supplement: "Equation",
    kind: "subequation",
  )
)

#show figure.where(kind: "subequation"): set figure(numbering: n => numbering(
  "(1.1)",
  ..(counter(heading).get().first(), counter(math.equation).get().first() + 1),
))



#subequation([$ a $ <a>], [ $ b $ <b>]) <both>
@label3 consists of @label and @label2

I’m getting quite close. The label works properly, i.e. @a references equation (1.23a). I can’t, however, reference both equations at once using the @both label. I understand why, but like to find a workaround anyways.

Any ideas?

EDIT: I updated my code. Now both correctly references (1.23). Maybe somebody has us for the example.

What does not work, however, is alignment using &…