Cross-reference of manually labeled equations in word documents

[mattocci27]

In the example below, I want to label g = h + i with (2) but it starts from (1). This can be handled with \stepcounter{} and \tag{} for LaTex but it doesn't work for word documents. Is it possible to do cross-reference of manually labeled equations in word documents?

---
format:
  docx:
    html-math-method: katex
---

$$
a = b + c \qquad(1a)
$$

$$
d = e + f \qquad(1b)
$$

$$
g = h + i
$$ {#eq-test}

$$
j = k + l
$$ {#eq-test2}

---
crossref:
  eq-prefix: Eq.
format:
  pdf:
    number-sections: true
    colorlinks: true
    pdf-engine: pdflatex
---

This is an example for PDF.

\begin{align}
a = b + c \label{eq:test_a} \tag{1a}
\end{align}

\begin{align}
d = e + f \stepcounter{equation} \label{eq:test_b} \tag{1b}
\end{align}

$$
g = h + i
$$ {#eq-test}

$$
j = k + l
$$ {#eq-test2}

Eq. \ref{eq:test_a}

Eq. \ref{eq:test_b}

@eq-test

@eq-test2