making a data frame reactive to SelectInput()

I have two data frames df and df2. As per code below df2 should contain data from df when filtered by dateRangeInput(). However, df2 is not reacting to a selected date range when new rows added to df. What am I missing in the code below?

library(data.table)
library(shiny)
library(shinydashboard)
library(lubridate)
library(rhandsontable)

df <- data.table(
  dasa = as.character(c("01/05/2024", "04/06/2024")),
  nasa = as.numeric(2,3),
  casa = as.character(c("abc", "def")),
  stringsAsFactors = FALSE
)

cc <- strsplit(df$dasa,"/",fixed=TRUE)
d <- unlist(cc)[3*(1:length(df$dasa))-2]
m <- unlist(cc)[3*(1:length(df$dasa))-1]
y <- unlist(cc)[3*(1:length(df$dasa))]
df$das <- paste0(y,"-",m,"-",d)

ui <- dashboardPage(
  dashboardHeader(title = "Financial Statements"),
  dashboardSidebar(
    menuItem("Home", tabName = "home"),
    menuItem("Accounting", tabName = "Recognition",
             menuSubItem("item1", tabName = "Item1")
    )
  ),
  dashboardBody(
    tabItems(
       tabItem(
        tabName = "Item1",
        fluidRow(
          column(
            width = 6,
            "Trial1_col1",
            rHandsontableOutput("Trial1_Item1")
          ),
          column(
            width = 6,
            "Trial1_col2",
            selectInput("choices", "Choose an option:",
                        choices = c("choice 1", "choice 2")),
            uiOutput("nested_ui")
          ),
          column(
            width = 6,
            "Trial1_col3",
            rHandsontableOutput("Trial1_Item2")
          )
        )
      )
    )
  )
)

server <- function(input, output) {
  data <- reactiveValues()

  observe({
    data$df <- as.data.frame(df)
  })

  observe({
    if (!is.null(input$Trial1_Item1))
      data$df <- hot_to_r(input$Trial1_Item1)
  })

  observe({
    if (!is.null(input$Trial1_Item2))
      data$df2 <- hot_to_r(input$Trial1_Item2)
  })

  observe({

    if (!is.null(input$dates)) {
      selected_dates <- seq(as.Date(input$dates[1]),
                            as.Date(input$dates[2]), by = "day")
      data$df2 <- df[as.Date(df$das) %in% selected_dates, ]
    } else {
      selected_dates2 <- unique(df$dasa)
      data$df2 <- df[df$dasa %in% selected_dates2, ]
    }
  })

  output$Trial1_Item1 <- renderRHandsontable({
    rhandsontable(data$df[,c(1:3)], stretchH = "all", rowHeaderWidth = 50, height = 300) |>
      hot_col(1, format = "%d.%m.%Y", type = "date")
  })

  output$nested_ui <- renderUI({
    if (input$choices == "choice 1") {
      dateRangeInput("dates", "Select a date range:", format = "dd/mm/yyyy",
                     start = "2024-01-01", end = Sys.Date())
    } else if (input$choices == "choice 2") {
      textInput("text", "Enter some text:")
    }
  })

  output$Trial1_Item2 <- renderRHandsontable({
    rhandsontable(data$df2[,c(1:3)], stretchH = "all", rowHeaderWidth = 50, height = 300) |>
      hot_col(1, format = "%d.%m.%Y", type = "date")
  })
}

shinyApp(ui, server)

You need to use the updated data frame data$df to update data$df2. Try this

library(data.table)
library(shiny)
library(shinydashboard)
library(lubridate)
library(rhandsontable)

df <- data.table(
  dasa = as.character(c("01/05/2024", "04/06/2024")),
  nasa = as.numeric(2,3),
  casa = as.character(c("abc", "def")),
  stringsAsFactors = FALSE
)

cc <- strsplit(df$dasa,"/",fixed=TRUE)
d <- unlist(cc)[3*(1:length(df$dasa))-2]
m <- unlist(cc)[3*(1:length(df$dasa))-1]
y <- unlist(cc)[3*(1:length(df$dasa))]
df$das <- paste0(y,"-",m,"-",d)

ui <- dashboardPage(
  dashboardHeader(title = "Financial Statements"),
  dashboardSidebar(
    menuItem("Home", tabName = "home"),
    menuItem("Accounting", tabName = "Recognition",
             menuSubItem("item1", tabName = "Item1")
    )
  ),
  dashboardBody(
    tabItems(
      tabItem(
        tabName = "Item1",
        fluidRow(
          column(
            width = 6,
            "Trial1_col1",
            rHandsontableOutput("Trial1_Item1")
          ),
          column(
            width = 6,
            "Trial1_col2",
            selectInput("choices", "Choose an option:",
                        choices = c("choice 1", "choice 2")),
            uiOutput("nested_ui")
          ),
          column(
            width = 6,
            "Trial1_col3",
            rHandsontableOutput("Trial1_Item2")
          )
        )
      )
    )
  )
)

server <- function(input, output) {
  data <- reactiveValues()
  
  observe({
    data$df <- as.data.frame(df)
  })
  
  observe({
    if (!is.null(input$Trial1_Item1)) {
      dfa <- hot_to_r(input$Trial1_Item1)
      cc <- strsplit(dfa$dasa,"/",fixed=TRUE)
      d <- unlist(cc)[3*(1:length(dfa$dasa))-2]
      m <- unlist(cc)[3*(1:length(dfa$dasa))-1]
      y <- unlist(cc)[3*(1:length(dfa$dasa))]
      dfa$das <- paste0(y,"-",m,"-",d)
      data$df <- dfa
      # print(data$df)
      if (!is.null(input$dates)) {
        # print(input$dates[2])
        df1 <- data$df
        selected_dates <- seq(as.Date(input$dates[1]),
                              as.Date(input$dates[2]), by = "day")
        data$df2 <- df1[as.Date(df1$das) %in% selected_dates, ]
      } else {
        selected_dates2 <- unique(dfa$dasa)
        data$df2 <- dfa[dfa$dasa %in% selected_dates2, ]
      }
      # print(data$df2)
    }
  })
  
  observe({
    if (!is.null(input$Trial1_Item2))
      data$df2 <- hot_to_r(input$Trial1_Item2)
  })
  
  output$Trial1_Item1 <- renderRHandsontable({
    rhandsontable(data$df[,c(1:3)], stretchH = "all", rowHeaderWidth = 50, height = 300) |>
      hot_col(1, format = "%d/%m/%Y", type = "date")
  })
  
  output$nested_ui <- renderUI({
    if (input$choices == "choice 1") {
      dateRangeInput("dates", "Select a date range:", format = "dd/mm/yyyy",
                     start = "2000-01-01", end = Sys.Date())
    } else if (input$choices == "choice 2") {
      textInput("text", "Enter some text:")
    }
  })
  
  output$Trial1_Item2 <- renderRHandsontable({
    rhandsontable(data$df2[,c(1:3)], stretchH = "all", rowHeaderWidth = 50, height = 300) |>
      hot_col(1, format = "%d/%m/%Y", type = "date")
  })
}

shinyApp(ui, server)