based on pandoc-eqnos, I can do some simple numbered work in converting markdown to docx.
however, the style in docx seems wrong.
in current style, the equation and number looks like below

where the equation and number are both in OMML, and there are two space between equation and number.
More common style for numbered equation is as below:

equation and number are in a three-column table.
equation is centered and number is right-aligned .
and the number should be plain text not in OMML.
I have tried code below:
+----+:-----------------:+--------------:+
| | $$y=f(x)$$ | {#eq:1} |
+-----+-----------------+---------------+
and pandoc-eqnos failed.