Resolved: multiple plots in Shinyapp

   library(shiny)
    library(ggplot2)
    library(dplyr)
    library(shinyWidgets)
    
    DF <- data.frame(dose = c("D1", "D2", "D3", "D1", "D2", "D3", "D1", "D2", "D3"),
                     len = c(4.2, 10, 29.5, 5, 7, 15, 20, 50, 40), 
                     by = c("by.1", "by.1","by.1","by.2","by.2","by.2", "by.3", "by.3", "by.3"))
    
    ui <- fluidPage(
      titlePanel("Plot By by"),
      sidebarLayout(
        sidebarPanel( width = 2, selectizeInput(inputId = "by", 
                                                label = "dataset by",
                                                choices = c("by.1", "by.2", "by.3"), 
                                                selected = "by.1",
                                                multiple = T,
                                                options = list('plugins' = list('remove_button')))
        ),
        mainPanel(
          plotOutput("distPlot")
        )
      )
    )
    
    server <- function(input, output) {
      output$distPlot <- renderPlot({
        
        mycols <- c("#92d050", "#57d3ff", "#ffc000")
        
        DF <- DF %>%
          arrange(desc(len)) %>%
          mutate(fills = ifelse(row_number() <= length(mycols), mycols, "grey50")) %>% filter(by %in% input$by)
        
        ggplot(data = DF, aes(x = len, y = reorder(dose, len))) +
          geom_col(aes(fill = I(fills)))+
          geom_text(aes(x = len/2, label = glue::glue("{dose} ({len}%)"))) +
          theme_minimal() +
          ## remove expansion and x title
          scale_x_continuous(NULL, expand = c(0,0)) +
          # remove the y bits
          theme(axis.ticks.y = element_blank(), 
                axis.title.y = element_blank()#, 
                #axis.text.y = element_blank()
                )
      })
    }
    
    shinyApp(ui = ui, server = server)

  Plot 1
  Plot 2
  Plot 3

library(shiny)
library(ggplot2)
library(dplyr)
library(shinyWidgets)

DF <- data.frame(dose = c("D1", "D2", "D3", "D1", "D2", "D3", "D1", "D2", "D3"),
                 len = c(4.2, 10, 29.5, 5, 7, 15, 20, 50, 40), 
                 by = c("by.1", "by.1","by.1","by.2","by.2","by.2", "by.3", "by.3", "by.3"))

ui <- fluidPage(
  titlePanel("Plot By by"),
  sidebarLayout(
    sidebarPanel( width = 2, selectizeInput(inputId = "by", 
                                            label = "dataset by",
                                            choices = c("by.1", "by.2", "by.3"), 
                                            selected = "by.1",
                                            multiple = T,
                                            options = list('plugins' = list('remove_button')))
    ),
    mainPanel(
      plotOutput("distPlot")
    )
  )
)

server <- function(input, output) {
  output$distPlot <- renderPlot({
    
    mycols <- c("#92d050", "#57d3ff", "#ffc000")
    
    DF <- DF %>%
      arrange(desc(len)) %>%
      mutate(fills = ifelse(row_number() <= length(mycols), mycols, "grey50")) %>% filter(by %in% input$by)
    
    ggplot(data = DF, aes(x = len, y = reorder(dose, len))) +
      geom_col(aes(fill = I(fills)))+
      geom_text(aes(x = len/2, label = glue::glue("{dose} ({len}%)"))) +
      facet_wrap(.~by, ncol=1) +
      theme_minimal() +
      ## remove expansion and x title
      scale_x_continuous(NULL, expand = c(0,0)) +
      # remove the y bits
      theme(axis.ticks.y = element_blank(), 
            axis.title.y = element_blank()#, 
            #axis.text.y = element_blank()
      )
  })
}

shinyApp(ui = ui, server = server)