Access math.equation numbering and labeling in template

I am writing a template for my reports in Typst and I want to move the following part of the code (it only enumerates labeled equations) from my main script, where it works fine, to my template script.

#set math.equation(numbering: "(1)")
#show math.equation: set block(breakable: true)

#show ref: it => {
  [equation #numbering(
      it.element.numbering,
      ..counter(math.equation).at(it.element.location())
    )]
}

#show math.equation: it => {
  if it.block and not it.has("label") [
    #counter(math.equation).update(v => v - 1)
    #math.equation(it.body, block: true, numbering: none)#label("")
  ] else {
    it
  }  
}

When I moved this part of code to a function conf() in template that wraps the document, there were no compiling errors in the template, however when I tried to reference to an equation, I got an error "cannot reference equation without numbering".

I tried to make another function, that I pass equations into, since I assume the error arises from the show rules, as they apply only to the script they are written in. Here is the function I've written in my template script

#let customEq(content) = {
  set math.equation(numbering: "(1)")
  show math.equation: set block(breakable: true)

  show ref: it => {
    [equation #numbering(
        it.element.numbering,
        ..counter(math.equation).at(it.element.location())
      )]
  }

  show math.equation: it => {
    if it.block and not it.has("label") [
      #counter(math.equation).update(v => v - 1)
      #math.equation(it.body, block: true, numbering: none)#label("")
    ] else {
      it
    }  
  }

  content
}

and here is the code I wrote in my main script to filter out equations that are written in text

#show math.equation: it => {
  if it.block {
  customEq(it.body)
  } else {
    it
  }
}

but the compiling error remains the same. I hope the question is well structured, as it is my first time writing on this platform. Thank you for the answers in advance!

The missing part seems to be the show: conf or show: customEq in the main document to "activate" the show and set rules.

I've tried your code and could make it work, so to me, it is only a question of how you import and declare your code in the two typ files.

//template.typ
#let conf(body) = {
  // set and show rules
  body
}

//main.typ
#import "template.typ":*

#show: conf

$ x + y $ <test>

If you want some ideas on how to reduce your code to something simpler, depending on what you need, you could use: (credit to Typst forum post)

//template.typ
#let customEq(body) = [
  #show math.equation: it => {
    if it.numbering == none and it.has("label") {
      math.equation(it.body, numbering: "(1)", block: true)
    } else { it }
  }
  #body
]

//main.typ
#import "template.typ": *

#show: customEq

$ x + y $
$ a + b $ <xyz>
$ c + d $ <abc>

Also, have you had a look at the Typst package equate?