Advice over limited regexp

What kind of regexp would you apply, and where, to change opening quotation marks " to <q> and closing ones to </q> ?
I think it should be applied to .Content.
But there’s no group extraction.

You could try to set the quotes for Goldmark’s typographer extension. There’s an example in the Goldmark config in the documentation.

No, because I want to style the quotation element ! The extension gives no freedom.