Connect bars with lines in R plotly

I am trying to connect the stacked bars with lines.

Expectation :

However I am unable to draw the lines between the bars. Have tried with the following script however it is not adding the line.

Using add_trace instead of 'add_lines' is not working.

df = data.frame(Aria = 20:25, Acqua = 21:26, Fuoco = 22:27, 
                Terra = 23:28, Cielo = 24:29, 
                Labels = c( 'Antonio', 'Maria', 'Giovanni',
                            'Sergio', 'Giorgio', 'Michele' ) )

evo_bar_plot_variant = function(plot_data, var_x, x_name = 'X axis', 
                                y_name = 'Y axis', ... ){
  df = data.frame(plot_data) 
  df = na.omit(df)
  var = quos(...) 
  names_vars = names( var )
  y_vars = names_vars[ startsWith( names_vars, 'var_y' ) ]
  y_var_names = sapply(1:length(y_vars), function(j){ 
                          quo_name(var[[y_vars[j]]] )})
  row_sum = df %>% 
              select( y_var_names ) %>% 
              rowSums()
  xenc = enquo( var_x )
  cols = colorRampPalette(c("white", "#4C68A2"))( length( y_vars ) )

  #... Plot parameters .....
  font_size = list( size = 12, family = 'Lato' )
  gray_axis = '#dadada'
  p = plot_ly(data = df, x = xenc, y = var[[ y_vars[1] ]], 
              name = quo_name( var[[ y_vars[1] ]] ), 
              type = 'bar', marker = list( color = cols[1], 
              line = list( color = '#E1E1E1', width = 0.8 ) ), 
              hoverlabel = list( font = font_size ) ) %>%
    layout(title = list( text = 'Bar', x = 0 ), barmode = 'stack',
           yaxis = list( title = y_name, showgrid = F, 
           zerolinecolor = gray_axis,
           titlefont = font_size, side = 'right' ),
           xaxis = list(title = x_name, linecolor = gray_axis,
                        zerolinecolor = gray_axis,
                        tickfont = font_size, titlefont = font_size),
           legend = list(font = font_size, orientation= 'h', 
                         font = font_size, x = 1 , y = 1.2, 
                         xanchor = "left", yanchor = 'top' ))

  if( length( y_vars ) >= 2 ){
    for( i in 2:length( y_vars ) ){
      p = p %>% 
            add_trace(y = var[[ y_vars[i] ]], 
                      name = quo_name( var[[ y_vars[i] ]] ), 
                      marker = list(color = cols[i], 
                      line = list(color = '#E1E1E1', width = 0.8)), 
                      hoverlabel = list(font = font_size))
    }
  }

  p =  p %>% 
        add_annotations(xref = 'x', yref = 'y', 
                        y = ( row_sum ) + 5, x = xenc,
                        text = paste( row_sum ), 
                        font = font_size, showarrow = F )

  p      
}

evo_bar_plot_variant( df, var_x = Labels, var_y1 = Aria, var_y2 = Acqua, var_y3 = Fuoco, var_y4 = Terra,
              var_y5 = Cielo )

Getting output like this :