how to show a value (calculated with shiny server) in a quarto dashboard valuebox

I'm trying to build a dashboard with Quarto. One initial goal is to count the number of cases in a dataset (later with API retrieval) when the dashboard is called on the Shiny server. In the 'server' context, I render the n-count with output$n <- renderText(nrow(data), and then attempt to retrieve it in a valuebox with textOutput("n"). However, I only see code in the boxes, not the count. What am I doing wrong? (I've tried several variations):

  ---
  title: "Count N"
  format: dashboard
  server: shiny
  ---

  ```{r}
  #| context: setup

  data <- tibble::tibble(a = c(1, 2, 3)) # The data should always be retrieved from a server when the dashboard starts later, that's why I need the server context

  ```

  ## Row 

  ```{r}
  #| content: valuebox
  #| title: "n1"

  # renderText() with paste0

  list(
    value = textOutput("n1")
  )
  ```

  ```{r}
  #| content: valuebox
  #| title: "n2"

  # renderText() without paste0

  list(
    value = textOutput("n2")
  )
  ```

  ```{r}
  #| content: valuebox
  #| title: "n3"

  # it works with a blank (but boring) number

  list(
    value = 99
  )
  ```


  ```{r}
  #| context: server

  n <- data |> nrow() |> as.character()

  output$n1 <- renderText(n)

  output$n2 <- renderText(paste0(n))
  ```

My output looks like this:

As described here you can use the value_box from the bslib package to create a dynamic value box. Make sure you create a reactive value like this:

---
title: "Count N"
format: dashboard
server: shiny
---

```{r}
#| context: setup
library(shiny)
data <- tibble::tibble(a = c(1, 2, 3)) # The data should always be retrieved from a server when the dashboard starts later, that's why I need the server context

```

## Row 

```{r}
library(bslib)
library(bsicons)
value_box(
  id = "card1",
  title = "n1",
  value = textOutput("n1")
)
```

```{r}
#| content: valuebox
#| title: "n3"

# it works with a blank (but boring) number

list(
    value = 99
)
```


```{r}
#| context: server

n <- reactive({
  data |> nrow() |> as.character()
})
output$n1 <- renderText({n()})
```

Output: