YAML for docx creates html

Question

I use RStudio with Quarto to create an word-document. The YAML-Line for that is simply format: docx

That works with out any problems.

But for reasons I dont quite understand, when creating a flextable with an image the word document cant be opend after rendering. So I changed the YAML to output: officedown::rdocx_document

Now the flextable is created with the image but the document is not an .docx anymore, but an .html.

Does anyone no why or has an solution for this?

I although tried following code, the result is still a .html file

---
date: "`r Sys.Date()`"
author: "Your Name"
title: "Untitled"
output: 
  officedown::rdocx_document
---

{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE, fig.cap = TRUE)
library(officedown)

{r}
library(flextable)
library(officer)

img.file <- file.path( R.home("doc"), "html", "logo.jpg" )

myft <- flextable( head(iris))

myft <- compose( myft, i = 1:3, j = 1,
                 value = as_paragraph(
                   as_image(src = img.file, width = .20, height = .15),
                   " blah blah ",
                   as_chunk(Sepal.Length, props = fp_text(color = "red"))
                 ),
                 part = "body")

autofit(myft)

Thank you!