How to customize barchart in plotly R?

On barchart: 'sale' and 'share' variables are visualized via bars, while 'cost' by a red line. Now I want to drop/remove this red line and keep only numbers into boxes and add corresponding variable in the legend map. Moreover I want to add average value of 'share' as a horizontal line on the Y axis

df <- data.frame (model  = c("A", "B", "C","D","E","F"),
                      share = c(12,20,15,9,60,20),
                      sale = c(16,25,18,14,67,28),
                      cost = c(14,19,28,24,57,28))

#set levels of model by cost
df$model <- factor(df$model, levels = arrange(df, desc(df$cost))$model)

library(tidyverse)

df_long <- df %>% 
  pivot_longer(
    cols = -model
  ) 


df_long %>% 
  filter(name != "cost") %>% 
  plot_ly(x = ~model, y = ~value, color = ~name, type = "bar", 
          customdata = ~name,  colors = c("blue", "gray"),
          hovertemplate = paste0("Model: %{x}<br>Value: %{y}<br>",
                                 "Name: %{customdata}<extra></extra>")) %>%
  add_lines(inherit = F, data = df, x = ~model, 
            y = ~cost, color = I("red"),
            name = "cost",
            hovertemplate = paste0("Model: %{x}<br>Value: %{y}<br>",
                                   "Name: cost<extra></extra>")) %>% 
  add_annotations(data = df, x = ~model, y = ~cost, text = ~cost,
                  bgcolor = "white", bordercolor = "black", 
                  xshift = 15, yshift = 15, showarrow = F) %>% 
  layout(barmode = "group")