So this is the functionality I want, but I want to use flexdashboard… Is this even possible? In particular I want the user to be able to filter the table and then click to make the final selection.

library(shiny)
library(DT)
#> 
#> Attaching package: 'DT'
#> The following objects are masked from 'package:shiny':
#> 
#>     dataTableOutput, renderDataTable
library(shinyWidgets)
ui <- fluidPage(
  selectizeGroupUI(
    id = "my-filters",
    params = list(
      var_one = list(inputId = "speed", title = "Speed", placeholder = 'select'),
      var_two = list(inputId = "dist", title = "Distance", placeholder = 'select')
    )
  ),
  fluidRow(
    column(6, DT::dataTableOutput('x1')),
    column(6, plotOutput('x2', height = 500))
  )
)

server <- function(input, output, session) {
  res_mod <- callModule(
    module = selectizeGroupServer,
    id = "my-filters",
    data = cars,
    vars = c("speed", "dist")
  )
  output$x1 = DT::renderDataTable(res_mod(), server = TRUE, selection = 'single')
  output$x2 = renderPlot({
    row_selected = input$x1_rows_selected
    par(mar = c(4, 4, 1, .1))
    plot(cars)
    if (length(row_selected)>0) points(res_mod()[row_selected, ], pch = 19, cex = 2)
  })
}

shinyApp(ui, server)

^{Created on 2022-09-17 with reprex v2.0.2}